Physics 20 Practice final

Multiple ChoiceIdentify the choice that best completes the statement or answers the question.

A Student’s ExcursionA student walks out of her science classroom and heads 15.0 m [north] to the washroom. She leaves the washroom and heads 40.0 m [south] to the math classroom.

____ 1. Refer to the information in A Student’s Excursion to answer the following question. The distance the student has travelled from the science classroom to the math classroom is a. 15.0 m c. 40.0 mb. 25.0 m d. 55.0 m

Car A begins at 5 m.Car B begins at 0 m.

____ 2. Refer to the position-time graph above to answer this question. Which of the following statements is true at t = 0.0 s?a. Car A and Car B are at the same starting position.b. Car A has a greater velocity than Car B.c. Car A is moving and Car B is at rest.d. Car A is ahead of Car B.

____ 3. Two friends decide to have a friendly race on their bikes. The girl travels at a speed of 6.0 m/s while her boyfriend speeds off in the same direction at a speed of 6.5 m/s. If they both start from the same starting point, how much farther will the boyfriend have travelled in 15 s?a. 0.50 m c. 6.5 m b. 6.0 m d. 7.5 m

BusA bus, initially at rest, pulls away from a bus stop with a constant acceleration of 1.50 m/s2 [E].

____ 4. Refer to the information in Bus to answer this question. The distance required for the bus to reach a velocity of 60.0 km/h [E] isa. 12.2 m c. 333 mb. 92.6 m d. 1.20 103 m

Double PlayIn an attempt to make a double play during a baseball game, the third baseman, at a position 15 m [E] of the shortstop, relays the ball to the second baseman, at a position 15 m [W] of the shortstop.(1 tick = 15 m)(Let X represent the origin at the shortstop.)

____ 5. Refer to the information in Double Play to answer this question. The correct representation of the displacement vector, , for the ball isa. c.

b. d.

____ 6. By definition, the displacement of an object is given with respect to thea. initial position c. initial originb. final position d. final origin

Football Throw with the Wind

A quarterback throws a football at a velocity, , of 60.0 km/h [E], to a receiver whose position, relative to the quarterback, is 40.0 m [E]. A wind is blowing from the west at a

speed of 30.0 km/h, .(1 tick = 30 km/h)

____ 7. Refer to the information in Football Throw with the Wind to answer this question. The vector that correctly

represents the resultant velocity, , of the football relative to the ground isa. c.

b. d.

Swimming in a River

____ 8. Refer to the information in Swimming in a River to answer this question. To reach point Y, directly across the river, the swimmer should head (not possible since swimmer is slower than current- hypotenuse of triangle would be smaller than current))a. 14 [N of W] c. 14 [E of N]b. 76 [W of N] d. 76 [E of N]

Nerf® BallA Nerf® ball is launched horizontally from a rooftop and lands on the ground, 3.50 m from the base of the building, in a time of 2.20 s.

____ 9. Refer to the information in Nerf® Ball to answer this question. The horizontal speed of the ball isa. 0.0629 m/s c. 7.70 m/sb. 1.59 m/s d. 21.6 m/s

Ball ThrowA ball is thrown into the air at an angle of 60.0 and lands on the ground 40.0 m away in 2.80 s.

____ 10. Refer to the information in Ball Throw to answer this question. The vertical component of the velocity isa. 14.3 m/s c. 24.7 m/sb. 16.5 m/s d. 28.6 m/s

____ 11. Which of the following quantities is a scalar quantity?a. displacement c. distanceb. acceleration d. velocity

____ 12. The following table contains data collected from an experiment investigating an object’s motion.

Time (s) Position (m) [right]

0.0 0.00.1 4.0

0.2 8.00.3 12.00.4 16.00.5 20.0

Analyzing the data could lead to the conclusion that the object isa. at rest c. moving with increasing velocityb. moving with uniform velocity d. moving with decreasing velocity

____ 13. A car travelling on a level highway runs out of gas and coasts to a stop. What forces are acting on the car and in which directions while the car is coasting?a. force of gravity [down], applied force [forward], force of friction [backward], and normal

force [up]b. force of gravity [down], applied force [forward], force of friction [forward], and normal

force [up]c. force of gravity [down], force of friction [backward], and normal force [up]d. force of gravity [down], force of friction [forward], and normal force [up]

____ 14. The direction of the acceleration of a moving object is alwaysa. in the same direction as its initial velocity.b. in the same direction as its final velocity.c. in the same direction as the net force.d. in the opposite direction to the frictional force.

____ 15. A large steel ball bearing of mass 1.0 kg rolls down an inclined track where the force of friction is 2.0 N [up the track]. The component of the force of gravity down the track is 5.0 [N]. What is the acceleration of the ball bearing? a. 7.0 m/s2 [down the track] c. 3.0 m/s2 [up the track]b. 5.0 m/s2 [down the track] d. 3.0 m/s2 [down the track]

____ 16. A ball bearing falls from rest in oil. It experiences a retarding force that is directly proportional to its velocity. Which graph best represents the ball bearing’s acceleration, , as a function of elapsed time, ?

a. c.

b. d.

____ 17. An oak block is placed on a horizontal oak board, and the force needed to keep the block moving at a slow, constant velocity is measured. In each succeeding trial, another identical block is placed on top of the initial block to increase the mass of the system. Which graph best summarizes the relationship between the force of

kinetic friction, , and the normal force, ?a. c.

b. d.

____ 18.A penny, a quarter, and a toonie are released on Earth at the same time from a position 3.0 m above the floor. Assume that all coins have the same thickness and that they fall with their faces horizontal. Mass (m), cross-sectional area (A), and mass divided by cross-sectional area (m/A) are shown in the table for each coin. Which coin reaches the floor first in a vacuum?

Coin Mass, m (g)

Area, A (cm2)

Mass/Area, m/A (g/cm2)

penny 2.4 2.8 0.83quarter 5.9 4.3 1.4toonie 7.3 6.2 1.2

a. penny b. quarter c. toonied. all coins reach the floor at the same time

____ 19. An astronaut is standing on the surface of the Moon. Assume that the Moon suddenly shrinks to one-half its original diameter, but that its mass remains unchanged.

What will happen to the force of gravity acting on the astronaut?

a. It will remain unchanged. c. It will become four times greater.b. It will become twice as great. d. It will become half as great.

____ 20.An 80.0-kg athlete is standing on a bathroom scale in an elevator in a fitness centre on Earth, where the magnitude of the gravitational field strength, , is 9.81 N/kg. The reading on the bathroom scale is 981 N. What is the magnitude of the apparent weight of the athlete?

a. 196 N c. 981 Nb. 785 N d. 1.77 103 N

____ 21. A 65.0-kg athlete is exercising on a bathroom scale in an elevator in a fitness centre on Earth, where the magnitude of the gravitational field strength, , is 9.81 N/kg. At one instant of time, the reading on the

bathroom scale is 985 N. Which is the correct free-body diagram, drawn to scale, for this instant? is the

force of gravity, is the normal force, is the net force, and is the apparent weight.

a. c.

b. d.

____ 22. What is the direction of motion of the tip of the hand of a clock on a vertical wall at the instant the tip of the hand is passing over the digit "9" on the face of the clock?

a. to the left c. upwardb. to the right d. downward

____ 23. Mass A, moving in a circle of radius 1.50 m, takes 2.00 s to make one revolution. Mass B requires 1.00 s to make one revolution of a circle with a radius of 3.00 m. If both masses are equal, what is the ratio of the centripetal force (F) acting on A compared to that acting on B?

a. c.

b. d.

____ 24. When a car rounds a horizontal circular curve at a constant speed, which of the following must be true?

I. The net force on the car is zero.II. The friction exerted by the road on the car is directed sideways on the car.

III. The car's acceleration is constant.

a. I and II c. I and IIIb. II only d. III only

____ 25. A block rests on the floor of a merry-go-round that is gradually increasing its speed. Which of the following is true for this situation?

I. The block will stay motionless relative to the floor of the merry-go-round as long as the force of friction between the floor and the block is equal or greater than the centripetal force.

II. The centripetal force on the block is directly proportional to the speed of the merry-go-round.

III. The centripetal force on the block is directly proportional to the distance that the block is located from the centre of rotation.

a. I and II c. I and IIIb. II and III d. I, II, and III

____ 26. A cyclist pedals with a frequency of 90.0 rpm. What is the centripetal acceleration of the pedal if the distance from the pedal to its axis of rotation is 24.0 cm?

a. 4.21 m/s2 c. 3.39 m/s2

b. 10.7 m/s2 d. 21.3 m/s2

____ 27. Kepler's constant for Jupiter is 3.12 10–16 s2/m3. What is the tangential speed of a satellite that orbits about Jupiter with a radius of 9.50 108 m?

a. 5.77 103 m/s c. 3.67 103 m/sb. 1.15 104 m/s d. 3.63 104 m/s

____ 28. You drop a stone from a bridge so that the stone falls toward the river below the bridge. Ignoring air friction, which of the following best describes the mechanical energy of the stone?

a. Ek is increasing, Ep is decreasing, Em is decreasing.b. Ek is increasing, Ep is decreasing, Em is constant.c. Ek is decreasing, Ep is decreasing, Em is decreasing.d. Ek is decreasing, Ep is increasing, Em is constant.

____ 29. A roller coaster trolley with a mass of 2.30 103 kg begins to coast up a hill at a point 4.25 m above the ground. The trolley has an initial speed of 16.5 m/s. At the top of the hill that is 19.6 m above the ground, the trolley has a speed of 1.12 m/s. What is the work done on the trolley as it coasts up the hill?

a. 6.58 105 J c. 3.32 104 Jb. 6.00 104 J d. 3.47 104 J

____ 30. The energy-position graph shows the relationship between an object's kinetic and gravitational potential energies and its position. Which of the following best describes the state of the object?

a. The object is gaining mechanical energy.b. The object is losing mechanical energy.c. The object's mechanical energy is constant.d. Information on the mechanical energy of the object cannot be determined from this graph.

____ 31. A motor has a power rating of 125 kW. Assuming no energy is lost due to friction, how much work can the motor do in 2.50 h?

a. 1.88 107 J c. 2.16 107 Jb. 1.13 109 J d. 1.78 109 J

____ 32. A pendulum is pulled to the side and released. What is its frequency if it passes through its rest position 0.150 s after it is released?a. 1.67 Hz c. 6.67 Hzb. 3.33 Hz d. 7.50 Hz

____ 33. In an experiment to measure the frequency of a mass oscillating up and down on a spring, students observed that a mass passed through its equilibrium position 36 times in 6.5 s. What is the frequency of this harmonic oscillator?a. 5.5 Hz c. 2.8 Hzb. 1.4 Hz d. 2.1 Hz

Block on a SpringA block on a horizontal frictionless surface attached to a spring. Diagram is not to scale.

____ 34. Refer to the diagram Block on a Spring to answer this question.The block in the diagram is attached to a spring on a horizontal frictionless surface, as shown. When the block is released, it oscillates back and forth between the positions indicated by the vectors . Which points (I, II, and III) best indicate where the velocity of the block will be zero?a. I, II, and III c. II onlyb. I and II d. I and III

SlingshotA slingshot is pulled back in order to provide its pellet with energy. (The diagram is not to scale.)

____ 35. Refer to the diagram Slingshot to answer this question.

A 45.0-g pellet is placed in the rubber band of the slingshot. When the band is pulled back a distance of 42.0 cm and released, the initial acceleration of the pellet is 525 m/s2. What is the spring constant of the rubber band?a. 56.3 N/m c. 49.7 N/mb. 62.1 N/m d. 51.9 N/m

____ 36. A 24.8-kg mass, attached to a spring that has a spring constant of N/m, is free to oscillate on a horizontal frictionless surface. The mass is pulled to a position 7.25 cm [N] of its resting position. What will be the acceleration of the mass when it is released?a. 2.00 m/s2 [N] c. 2.31 m/s2 [N] b. 2.00 m/s2 [S] d. 2.31 m/s2 [S]

____ 37. A 7.50-kg mass is suspended at equilibrium on a spring that has a spring constant of N/m. If the mass is set into simple harmonic motion by pulling it down 3.50 cm and then releasing it, what is its speed when it passes through its equilibrium position?a. 0.398 m/s c. 0.487 m/sb. 0.452 m/s d. 0.513 m/s

____ 38. Europa, a moon of Jupiter, has a mass of 8.93 1022 kg and a radius of 1.83 106 m. On Europa, what is the period of a pendulum that has a length of 75.0 cm?a. 3.18 s c. 3.95 sb. 3.76 s d. 4.08 s

____ 39. A pulse that is travelling in a spring at a speed of 7.29 m/s takes 0.492 s to pass a point in the spring. How long is the pulse?a. 4.15 m c. 3.87 mb. 3.92 m d. 3.59 m

____ 40. A bat uses a frequency of for its echolocation whereas a dolphin uses a frequency of . If the speeds of sound in air and water are 328 m/s and 1550 m/s respectively, what is the ratio

of the wavelengths of the sound produced by the bat to those produced by the dolphin?a. c.

b. d.

____ 41. The speed of sound in air is 326 m/s. What is the speed of a jet if the frequency you hear for its engine is 1.25 times the true frequency?a. km/h c. km/hb. km/h d. km/h

Sand PendulumA pendulum bob consists of a small bucket filled with fine sand. As the pendulum oscillates, the sand pours out through a hole in the bottom of the bucket so that it leaves a trail of sand on the surface below. The rope attached to the trolley pulls it to the right at a constant velocity while the pendulum swings across the trolley at right angles to the direction of the trolley’s velocity.

(This diagram is not to scale.)

____ 42. Refer to the diagram Sand Pendulum to answer this question.When the -long pendulum is set in motion, it swings at right angles to the velocity of the trolley. What is the speed of the trolley if the sand from the pendulum creates a wave pattern on the surface of the trolley with a wavelength of 0.150 m?a. m/s c. m/sb. m/s d. m/s

Numeric Response

43. Perdita Felicien posted a time of 7.90 s in the 100-m hurdles. Her average speed is ______ m/s. (Record your three-digit answer on the answer sheet.)

44. A vacationer, on her newly purchased sailboat, moves at a constant velocity of 9.0 m/s [south] for 35 min, and then returns in the opposite direction at a speed of 4.0 m/s for 45 min. The displacement of the vacationer for this trip is a.b  10c m [S]. The values of a, b, and c, respectively, are ______, ______, and ______. (Record all three digits of your answer on the answer sheet.)

45. The most common configuration for an aircraft carrier is a flat top deck that serves as a takeoff and landing area for airplanes. To land on the carrier, incoming airplanes moving at 241 km/h are equipped with tailhooks to engage arresting cables stretched across the deck. These cables can stop the aircraft within 97.5 m after it engages a cable.

The time it takes an aircraft to come to a complete stop by engaging tailhooks to the arresting cables across the deck is ______ s. (Record your three-digit answer on the answer sheet.)

RabbitA rabbit leaps into the air at an angle of 30.0 and lands back on the ground 8.00 m away in a time of 1.50 s.

46. Refer to the information in Rabbit to answer this question. The vertical component of the velocity of the rabbit at the instant before it lands on the ground is ______ m/s. (Record your three-digit answer on the answer sheet.)You will get the answer shown by using the velocity vector diagram but a different answer (not possible) is obtained by using the vertical information. Bad question

47. A lawnmower handle makes an angle of 30.0 with the horizontal. If a student pushes the handle with a force of 85.0 N, the magnitude of the force moving the lawnmower forward is _____ N. (Record your three-digit answer on the answer sheet.)

48. Use the following information to answer the next question.

Friction Definitions

1 Only has one value2 Present any time an object is sliding on another object3 Force exerted on an object at rest, preventing it from sliding4 Proportionality constant that ranges from zero to a maximum value

Match each of the friction definitions listed above with the term given below.

Coefficient of static friction ____ (Record in the first column.)Coefficient of kinetic friction ____ (Record in the second column.)Kinetic friction ____ (Record in the third column.)Static friction ____ (Record in the fourth column.)

(Record all four digits of your answer on the answer sheet.)

49. A pitcher throws a baseball at a speed of 25.0 m/s. The ball is spinning at a rate of 12.5 Hz. If the distance between the point where the pitcher releases the ball and the batter hits it is 20.5 m, then the ball will make _________ rotations as it travels from the pitcher to the batter. (Record your three-digit answer on the answer sheet.)

50. A dynamics cart with a mass of 0.875 kg is rolling at a speed of 3.60 m/s along a horizontal track. The cart comes to a hill and accelerates down the hill at a rate of 2.78 m/s2. If the length of the hill is 3.95 m, then, as the cart rolls down the hill, the gain in the its kinetic energy is ______ J. (Record your three-digit answer on the answer sheet.)

The diagram shows a block that is initially at rest on a frictionless ramp about to be released. The block will slide down the ramp and into the vertical loop. Diagram is not to scale.

51. Refer to the above diagram to answer this question.

In the above diagram, a 3.50 kg block is initially at rest at a height (h) of 1.40 m on a frictionless ramp. When released, the block accelerates down the ramp and into a vertical loop. If, for an instant at the highest point on the loop, the force that the loop exerts on the block is zero, then the radius (r) of the loop, in scientific notation, must be b 10w m. The value of b is ______. (Record your three-digit answer on the answer sheet.) This is a very challenging question using conservation of energy as well as forces to come up with two equations and two unknowns - you can omit it or accept the challenge!

52. If Earth's orbit about the Sun is a circle with a radius of , then Earth's tangential speed about the Sun is a.bc 10d m/s. The values of a, b, c, and d, respectively, are ______, ______, ______, and ______. (Record all four digits of your answer on the answer sheet.)

Compound Spring GraphForce versus Position Graph for a Compound Spring System

53. Use the Compound Spring Graph to answer this question. The graph shows the force required to compress a compound spring system. The spring constant between positions zero and 12.0 cm is N/m. The values of a, b, c, and d are ______, ______, ______, and ______. (Record all four digits on the answer sheet.)

54. A 35.0-kg mass is suspended at equilibrium on a spring that has a spring constant of N/m. The mass is pulled down to a position 18.5 cm below its equilibrium position, and then released. When the mass has risen a distance of 27.0 cm after being released, its acceleration is ______ m/s2. (Record your three-digit answer on the answer sheet.)

55. A sound wave has a speed of 335 m/s in air. If the frequency of the sound is 256 Hz, what is the wavelength of the sound? (Record your three-digit answer on the answer sheet.)

Closed-Pipe ResonanceA tuning fork held over a closed pipe produces resonance for particular lengths (L).

(This diagram is not to scale.)

56. Refer to the diagram Closed-Pipe Resonance to answer this question.When a tuning fork (A) is held over the tube, the shortest length (L) for which resonance occurs is 17.0 cm. Without changing the length of the tube, tuning fork A is replaced by tuning fork B. While tuning fork B is vibrating over the end of the tube, the tube is lengthened until the next point of greatest resonance is produced. If the frequency of tuning fork B is , the length of the tube for which resonance is heard is ______ cm. (Record your three-digit answer on the answer sheet.)

Two-point Interference PatternTwo in-phase point sources in a ripple tank, S1 and S2, generate the interference pattern shown below. S1 and S2 are apart. The maxima and minima are labelled from K to R.

57. Refer to the diagram Two-point Interference Pattern to answer this question.The generator is set to oscillate at a frequency of 4.50 Hz. If the distance between the two sources is 6.0 cm in the ripple tank, then the speed of the wave in the tank is ______ cm/s. (Record your two-digit answer on the answer sheet.)

Doppler WavesWhen a wave source is in motion, the wavelengths in front of and behind the source are altered.

(This diagram is not to scale.)

58. Refer to the diagram Doppler Waves to answer this question.The waves in the diagram were created in a ripple tank by a point source that oscillates at 2.80 Hz. The speed of the waves in the tank is 12.0 cm/s. If the source is moving at 3.60 cm/s, then the wavelength indicated by

is ______ cm. (Record your three-digit answer on the answer sheet.)

Essay

59. A football punter is practising to kick a football to achieve maximum height and maximum range. Assume that the velocity of each punt as it leaves his foot is the same. He kicks the ball at different angles and measures the height, the range, and the time that the ball is in the air.

a Describe the effect on the range, the height, and the time of flight as the angle of the kick is increased from 0 along the horizontal to 90 along the vertical.

b Explain which angle will achieve the maximum range and which angle will achieve the maximum height.

c Explain why a punter often prefers a punt at 45.0.d Prove that a punt at 20 will attain the same horizontal range as a punt at

70Assume that the initial speed is 30m/s and show your work.

60. A 20.0-kg curling stone is released at the hog line and moves 28.35 m [W] to sit on the button and score a point. If the coefficient of kinetic friction between the stone and the ice is 0.00200, what was the initial speed of the stone when it was released? (Ignore the curling of the stone because the slightly longer path of the stone is compensated for by the sweeping of the curlers.)

Physics 20 Practice finalAnswer Section

MULTIPLE CHOICE

1. ANS: D PTS: 1 DIF: moderate TOP: section 1.1KEY: distance travelled

2. ANS: D PTS: 1 DIF: moderate TOP: section 1.2KEY: motion of two objects

3. ANS: D PTS: 1 DIF: moderate TOP: section 1.2KEY: motion of two objects

4. ANS: B PTS: 1 DIF: moderate TOP: section 1.5KEY: kinematics

5. ANS: C PTS: 1 DIF: moderate TOP: section 2.1KEY: subtracting collinear vectors

6. ANS: A PTS: 1 DIF: easy TOP: section 2.1KEY: displacement

7. ANS: B PTS: 1 DIF: easy TOP: section 2.3KEY: collinear relative motion

8. ANS: D PTS: 1 DIF: challenge TOP: section 2.3KEY: non-collinear relative motion

9. ANS: B PTS: 1 DIF: moderate TOP: section 2.4KEY: projectile motion horizontally

10. ANS: C PTS: 1 DIF: moderate TOP: section 2.4KEY: projectile motion above the horizontal

11. ANS: C PTS: 1 DIF: easy TOP: section 1.1KEY: scalar quantity

12. ANS: B PTS: 1 DIF: moderate TOP: section 1.2KEY: uniform motion

13. ANS: C PTS: 1 DIF: moderate TOP: section 3.1KEY: force of friction|normal force|force of gravity|applied force

14. ANS: C PTS: 1 DIF: moderate TOP: section 3.3KEY: acceleration|net force|frictional force

15. ANS: D PTS: 1 DIF: moderate TOP: section 3.3KEY: Newton's second law|net force|mass|acceleration|friction

16. ANS: A PTS: 1 DIF: moderate TOP: section 3.3KEY: acceleration-time graph|force|Newton's second law|graph interpretation

17. ANS: D PTS: 1 DIF: moderate TOP: section 3.5KEY: force of kinetic friction|normal force|graph interpretation

18. ANS: D PTS: 1 DIF: easy TOP: section 4.1KEY: air resistance | acceleration due to gravity

19. ANS: C PTS: 1 DIF: easy TOP: section 4.2KEY: Newton's law of universal gravitation

20. ANS: C PTS: 1 DIF: moderate TOP: section 4.3KEY: apparent weight | true weight | elevator

21. ANS: B PTS: 1 DIF: moderate TOP: section 4.3KEY: free-body diagram | apparent weight | elevator

22. ANS: C PTS: 1 DIF: easy TOP: section 5.1KEY: circular motion

23. ANS: A PTS: 1 DIF: moderate TOP: section 5.1KEY: centripetal force | period

24. ANS: B PTS: 1 DIF: easy TOP: section 5.2KEY: centripetal acceleration

25. ANS: D PTS: 1 DIF: moderate TOP: section 5.2KEY: centripetal acceleration

26. ANS: D PTS: 1 DIF: easy TOP: section 5.2KEY: centripetal acceleration | frequency

27. ANS: B PTS: 1 DIF: moderate TOP: section 5.3KEY: Kepler's constant | orbital radius | velocity

28. ANS: B PTS: 1 DIF: easy TOP: section 6.2KEY: mechanical energy | work

29. ANS: D PTS: 1 DIF: moderate TOP: section 6.2KEY: kinetic energy | potential energy | work

30. ANS: C PTS: 1 DIF: easy TOP: section 6.3KEY: gravitational potential energy | kinetic energy | mechanical energy

31. ANS: B PTS: 1 DIF: easy TOP: section 6.4KEY: power | work

32. ANS: A PTS: 1 DIF: moderate TOP: section 7.1KEY: period | frequency

33. ANS: C PTS: 1 DIF: easy TOP: section 7.1KEY: period | frequency

34. ANS: D PTS: 1 DIF: easy TOP: section 7.2KEY: simple harmonic motion

35. ANS: A PTS: 1 DIF: moderate TOP: section 7.3KEY: Hooke's law | spring constant

36. ANS: B PTS: 1 DIF: moderate TOP: section 7.3KEY: spring constant | simple harmonic motion

37. ANS: C PTS: 1 DIF: moderate TOP: section 7.3KEY: spring constant | simple harmonic motion

38. ANS: D PTS: 1 DIF: challenge TOP: section 7.3KEY: simple harmonic motion | period

39. ANS: D PTS: 1 DIF: moderate TOP: section 8.2KEY: wave speed | medium

40. ANS: B PTS: 1 DIF: moderate TOP: section 8.2KEY: universal wave equation

41. ANS: A PTS: 1 DIF: moderate TOP: section 8.4KEY: Doppler effect

42. ANS: D PTS: 1 DIF: moderate TOP: section 7.3 | section 8.2KEY: period | simple harmonic motion | universal wave equation

NUMERIC RESPONSE

43. ANS: 12.7

PTS: 1 DIF: moderate TOP: section 1.2 KEY: average speed

44. ANS: 813

PTS: 1 DIF: moderate TOP: section 1.2 KEY: displacement45. ANS: 2.91

PTS: 1 DIF: moderate TOP: section 1.5 KEY: kinematics46. ANS: 3.08

PTS: 1 DIF: easy TOP: section 2.4KEY: projectile motion above the horizontal

47. ANS: 73.6

PTS: 1 DIF: moderate TOP: section 3.1 KEY: force48. ANS: 4123

PTS: 1 DIF: easy TOP: section 3.5KEY: coefficient of friction | static friction | kinetic friction

49. ANS: 10.3

PTS: 1 DIF: moderate TOP: section 5.1KEY: frequency | velocity | number of rotations

50. ANS: 9.61

PTS: 1 DIF: moderate TOP: section 6.1 KEY: kinetic energy | work51. ANS: 5.60

PTS: 1 DIF: challenge TOP: section 5.2 | section 6.2KEY: centripetal force | conservation of energy

52. ANS: 2974

PTS: 1 DIF: moderate TOP: section 5.2KEY: centripetal force | circular motion | velocity

53. ANS: 3333

PTS: 1 DIF: moderate TOP: section 7.2 KEY: Hooke's law | spring constant54. ANS: 2.99

PTS: 1 DIF: moderate TOP: section 7.3KEY: Hooke's law | simple harmonic motion

55. ANS: 1.31

PTS: 1 DIF: moderate TOP: section 8.2 KEY: universal wave equation56. ANS: 42.9

PTS: 1 DIF: challenge TOP: section 8.3KEY: closed pipe | resonance | standing waves

57. ANS: 6.8cm/s

PTS: 1 DIF: challenge TOP: section 8.3

KEY: maximum | minimum | interference | universal wave equation58. ANS: 3.00

PTS: 1 DIF: challenge TOP: section 8.4 KEY: Doppler effect

ESSAY

59. ANS:

a As the angle of the kick increases from 0 to 90, the x component of the initial velocity decreases, but the time of flight gradually increases. The horizontal range of the kick increases until 45, when it becomes a maximum, and then the horizontal range decreases from 45 to 90.As the angle of the kick increases from 0 to 90, the y component of the initial velocity increases. The height of the kick gradually increases until it reaches a maximum when the ball is kicked almost vertically.The time of flight is at a maximum when the acceleration due to gravity acts the longest. This occurs when the initial velocity is almost vertical.

b If the punter wishes to achieve the longest punt, then a kick at 45 is preferred. However, if the punter desires a longer hang-time, then a kick at more that 45 is preferred.

(c) A punter often prefers a punt at 45.0 because he wants to achieve maximum range.

d Assume that the initial speed is 30 m/s.

If the ball is kicked at an angle of 20, then:

The time of flight is:

Total time is 2 1.05 s = 2.10 s.The range is:

If the ball is kicked at an angle of 70, then:

vy =sin 70 (30 m/s) = 28.2 m/s (ignore next line)The time of flight is:

Total time is 2 2.87 s = 5.74 s.The range is:

The range is therefore the same at both angles.

PTS: 15 DIF: challenge TOP: section 2.4KEY: projectile motion above the horizontal

60. ANS:The kinetic friction of the ice on the stone gives it a negative acceleration. Once you know the acceleration, you can calculate the speed. Consider west to be the positive direction.

= (0.00200)(– 9.81 m/s2)= – 0.01962 m/s2

vf2 = vi

2 + 2advi

2 = vf2 – 2ad

= 0 – 2(–0.01962 m/s2)(28.35 m) = 1.112 m2/s2

vi = 1.05 m/s

The speed of the stone when it was released was 1.05 m/s [W].

PTS: 15 DIF: moderate TOP: section 3.5 KEY: coefficient of kinetic friction