1. joseph runs along a long straight track. the variation … test review – topic 2: mechanics...

IB Test Review – Topic 2: Mechanics Reagan IB Physics

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1. Joseph runs along a long straight track. The variation of his speed v with time t is shown below.

After 25 seconds Joseph has run 200 m. Which of the following is correct at 25 seconds?

Instantaneous speed / m s–1 Average speed / m s–1

A. 8 m s–1 8 m s–1

B. 8 m s–1 10 m s–1

C. 10 m s–1 8 m s–1

D. 10 m s–1 10 m s–1

(Total 1 mark)

2. The graph shows the variation with time t of the acceleration a of an object.

Which of the following is the change in velocity of the object in the time interval 0 to 4 s?

A. –8 m s–1

B. –4 m s–1

C. +4 m s–1

D. +8 m s–1 (Total 1 mark)

3. Samantha walks along a horizontal path in the direction shown. The curved part of the path is a semi-circle.

The magnitude of her displacement from point P to point Q is approximately

A. 2 m. C. 6 m.

B. 4 m. D. 8 m. (Total 1 mark)


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4. A car accelerates from rest. The acceleration increases with time. Which graph shows the variation with time t of the speed v of the car?

(Total 1 mark)

5. The graph shows how the displacement d of an object varies with time t. The tangent to the curve at time t1 is also shown.

Which of the following gives the speed of the object at point P?

A. the gradient at P

B. the shaded area

C.

D.

(Total 1 mark)

Pat gradient 1

1

1

td


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6. The graph is a speed versus time graph for an object that is moving in a straight line.

The distance travelled by the object during the first 4.0 seconds is

A. 80 m.

B. 40 m.

C. 20 m.

D. 5 m. (Total 1 mark)

7. The graph shows how the velocity of a particle varies with time.

Which of the following graphs correctly shows how the acceleration of the particle varies with time?


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(Total 1 mark)

8. A ball is thrown vertically upwards from the ground. The graph shows the variation with time t of

the vertical displacement d of the ball.

Which of the following gives the final displacement after time T and the average speed between time t = 0 and time t = T?

Displacement Average speed

A. 0 0

B. 0

C. 2D

D. 2D 0

(Total 1 mark) 9. Two identical metal spheres are held above the ground as shown.

The separation between them is small compared to their distance above the ground. When the spheres are released, the separation of the spheres will A. increase continuously. C. remain constant. B. increase initially and then remain constant. D. decrease continuously.

(1)

TD2

TD2

spheres

(not to scale)

ground


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10. A stone is thrown horizontally from the top of a high cliff. Assuming air resistance is negligible,

what is the effect of gravitational force on the horizontal and on the vertical components of the velocity of the stone? Vertical component of velocity Horizontal component of velocity A. increases to a constant value stays constant B. increases continuously stays constant C. increases to a constant value decreases to zero D. increases continuously decreases to zero

(1) 11. A stone is projected horizontally from the top of a cliff. Neglecting air resistance, which one of the

following correctly describes what happens to the horizontal component of velocity and to the vertical component of velocity?

Horizontal component of velocity Vertical component of velocity A. Decreases Increases B. Decreases Constant C. Constant Constant D. Constant Increases

(1)

12. A ball is thrown horizontally from the top of a cliff. Air resistance is negligible. Which of the following diagrams best represents the subsequent path of the ball?

(1)

13. Two stones, X and Y, of different mass are dropped from the top of a cliff. Stone Y is dropped a

short time after stone X. Air resistance is negligible.

Whilst the stones are falling, the distance between them will

A. decrease if the mass of Y is greater than the mass of X. B. increase if the mass of X is greater than the mass of Y. C. decrease whether the mass of X is greater or less than the mass of Y. D. increase whether the mass of X is greater or less than the mass of Y.

A.

C.

B.

D.


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14. A ball rolls off a horizontal table with velocity v. It lands on the ground a time T later at a distance

D from the foot of the table as shown in the diagram below. Air resistance is negligible.

A second heavier ball rolls off the table with velocity v. Which one of the following is correct for

the heavier ball?

Time to land Distance from table A. T D B. T less than D C. less than T D D. less than T less than D

(1) 15. An object has initial speed u and acceleration a. After travelling a distance s, its final speed is v.

The quantities u, v, a and s are related by the expression v2 = u2 + 2as. Which of the following includes the two conditions necessary for the equation to apply?

A. a has constant direction u and v are in the same direction B. a has constant direction a, u and v are in the same direction C. a has constant magnitude a has constant direction D. a has constant magnitude u and v are in the same direction

(1) 16. Two identical metal spheres X and Y are released at the same time from the same height above the

horizontal ground. Sphere X falls vertically from rest. Sphere Y is projected horizontally as shown below.

Air resistance is negligible. Which of the following statements is correct? A. Sphere X hits the ground before sphere Y because it travels a shorter distance. B. Sphere Y hits the ground before sphere X because its initial velocity is greater. C. The spheres hit the ground at the same time because horizontal motion does not affect

vertical motion. D. The spheres hit the ground at the same time because they have equal weights.

(1)

v

table

D

ground

X Y


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17. A particle is projected horizontally with speed v from a height H. It lands a horizontal distance R

from the point of launch as shown in the diagram below.

A second particle is projected horizontally from the same height with speed 2v. Neglecting air

resistance the horizontal distance travelled by this particle is A. R. B. C. 2R. D. 4R.

(1) 18. A stone is thrown horizontally from the top of a cliff with an initial speed v.

The time of flight of the stone is t and its range R. Air resistance is negligible. For a stone that is thrown horizontally from the top of the cliff with an initial speed 3v, which of

the following is correct?

Time of flight Range A. t R B. 3t 3R C. t 3R D. 3t R

(1) 19. An object is moving at constant velocity. Which one of the following quantities must have zero

magnitude?

A. Weight of object

B. Momentum of object

C. Kinetic energy of object

D. Resultant force on object (1)

v

H

R

.2R


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20. An elevator (lift) is used to either raise or lower sacks of potatoes. In the diagram, a sack of potatoes of mass 10 kg is resting on a scale that is resting on the floor of an accelerating elevator. The scale reads 12 kg.

The best estimate for the acceleration of the elevator is

A. 2.0 m s–2 downwards. C. 1.2 m s–2 downwards.

B. 2.0 m s–2 upwards. D. 1.2 m s–2 upwards. (1)

21. If the resultant external force acting on a particle is zero, the particle

A. must have constant speed.

B. must be at rest.

C. must have constant velocity.

D. must have zero momentum. (1)

22. A light inextensible string has a mass attached to each end and passes over a frictionless pulley as shown.

The masses are of magnitudes M and m, where m < M. The acceleration of free fall is g. The

downward acceleration of the mass M is

A. C.

B. D.

(1)

10 kgelevator

scale

pulley

string

mass m

mass M

� �� mM

gmM��

� �mMgmM

��

� �M

gmM �� mM

Mg�


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force 5.0N

23. A student is sitting on a chair. One force that is acting on the student is the pull of gravity. According to Newton’s third law, there must be another force which is

A. the upward push of the chair on the student.

B. the downward force on the student.

C. the downward push of the chair on Earth.

D. the upward force on Earth. (1)

24. A toy cannon is mounted vertically on a cart. The cart is moving along a straight-line with constant speed. A spring inside the cannon shoots a ball vertically upwards.

No resistance forces act on the cart and on the ball. Which one of the following statements is true about the position where the ball will land?

A. The position depends on the speed of the cart.

B. The ball will land behind the cannon.

C. The ball will land inside the cannon.

D. The ball will land in front of the cannon. (1)

25. Mandy stands on a weighing scale inside a lift (elevator) that accelerates vertically upwards as shown in the diagram below. The forces on Mandy are her weight W and the reaction force from the scale R.

The reading of the scale is

A. R + W. C. R.

B. W. D. R – W. (1)

cannon

cart

lift

scale

acceleration


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26. A body of weight 2W hangs vertically from a string attached to a body of weight W. Weight W is released and both bodies fall vertically.

Air resistance may be neglected. What is the tension in the string during the fall?

A. Zero C. 2W

B. W D. 3W (1)

27. Three forces of magnitude F1 = 3.0 N, F2 = 4.0 N and F3 = 6.0 N act at a point. The point is in equilibrium. The magnitude of the resultant of F1 and F2 is

A. 1.0 N. C. 6.0 N.

B. 5.0 N. D. 7.0 N. (1)

28. A trolley of mass 1.5 kg is pulled along a horizontal table by a force of 5.0N.

The frictional force acting on the trolley is 0.50N.

The acceleration of the trolley is

A. 0.30 m s–2. C. 3.0 m s–2.

B. 0.33 m s–2. D. 3.3 m s–2. (1)

29. The graph below shows the variation with displacement d of the force F applied by a spring on a cart.

The work done by the force in moving the cart through a distance of 2 cm is

A. 10 × 10–2J. B. 7 × 10–2J. C. 5 × 10–2J. D. 2.5 × 10–2J. (1)

5

4

3

2

1

00 1 2 3

d m / 10 –2

F N/

W

2W


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30. The variation with time of the vertical speed of a ball falling in air is shown below.

During the time from 0 to T, the ball gains kinetic energy and loses gravitational potential energy ΔEp. Which of the following statements is true?

A. ΔEp is equal to the gain in kinetic energy.

B. ΔEp is greater than the gain in kinetic energy.

C. ΔEp is equal to the work done against air resistance.

D. ΔEp is less than the work done against air resistance. (1)

31. The point of action of a constant force F is displaced a distance d. The angle between the force and the direction of the displacement is θ, as shown below.

Which one of the following is the correct expression for the work done by the force?

A. Fd B. Fd sin θ C. Fd cos θ D. Fd tan θ (1)

32. A body of mass m and speed v has kinetic energy EK. A second body of mass moves at speed

2v. The kinetic energy of this second body is

A. . B. EK. C. 2EK. D. 4EK.

(1)

time

Speed

00 T

d

F

2m

2KE


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33. A body moving along a straight-line has mass 3.0 kg and kinetic energy 24 J. The motion is then opposed by a net force of 4.0 N. The body will come to rest after travelling a distance of

A. 2.0 m. B. 6.0 m. C. 8.0 m. D. 12 m. (1)

34. A box of weight W is moved at constant velocity v along a horizontal floor. There is a constant frictional force F between the box and the floor.

What is the power required to move the box through a distance s?

A. Fs B. Fv C. Ws D. Wv (1)

35. An object of mass m falls from rest in a vacuum. As the object falls it loses an amount E of

gravitational potential energy. The speed of the object is then

A. . B. . C. . D. .

(1)

36. Which of the following quantities are conserved in an inelastic collision between two bodies?

Total linear momentum of the bodies Total kinetic energy of the bodies

A. yes yes

B. yes no

C. no yes

D. no no

(1)

37. An astronaut in outer space is holding a hammer and drifting at constant velocity. The astronaut throws the hammer in the opposite direction to that in which she is drifting.

What change, if any, occurs in the total kinetic energy and the total momentum of the astronaut and hammer?

Total kinetic energy Total momentum

A. unchanged increased

B. unchanged unchanged

C. increased increased

D. increased unchanged (1)

38. A constant force is applied to a ball of mass m. The velocity of the ball changes from v1 to v2. The impulse received by the ball is

A. m(v2 + v1). B. m(v2 – v1). C. m(v22 + v1

2). D. m(v22 – v1

2). (1)

mE2

Em2 m

E2E

m2


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7.0 ms–1

–13.0 ms

point X

point Y

before after

A. B.

C. D.

p

t0

0

p

t0

0

p

t0 0

p

t0 0

39. A ball of mass 2.0 kg falls vertically and hits the ground with speed 7.0 ms–1 as shown below.

before after

The ball leaves the ground with a vertical

speed 3.0 ms–1. The magnitude of the change in momentum of the ball is

A. zero. B. 8.0 Ns.

C. 10 Ns. D. 20 Ns. (1)

40. The momentum of a system is conserved if

A. no external forces act on the system. C. no kinetic energy is lost or gained by the system.

B. no friction forces act within the system. D. the forces acting on the system are in equilibrium.

(1)

41. The velocity of a body of mass m changes by an amount 'v in a time 't. The impulse given to the body is equal to

A. m't. B. C. D. m'v.

(1)

42. A ball is held at rest at point X and is then released. It drops on to a flat horizontal surface and rebounds to a maximum height at point Y.

Which one of the following graphs best shows the variation with time t of the momentum p of the ball as it moves between point X and point Y?

.tv

'' .

tvm''


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43. A small ball P moves with speed v towards another identical ball Q along a line joining the centres of the two balls. Ball Q is at rest. Kinetic energy is conserved in the collision.

Which one of the following situations is a possible outcome of the collision between the balls?

(1)

44. A ball of mass M hits a wall at speed V normal to the wall. It rebounds with speed v normal to the wall as shown below.

What is the magnitude of the change in momentum of the ball and the direction of the force that the wall exerts on the ball?

change in momentum direction of force

A. M(V – v) to the right

B. M(V – v) to the left

C. M(V + v) to the right

D. M(V + v) to the left (1)

P Q at rest

v

P Q

P Q

P Q

P Q

A. B.

C. D.

v v

v 3v44

v = 0 v

v v

2 2

wall

M

V

v

left right


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45. The diagram below shows a trolley of mass 4.0 kg moving on a frictionless horizontal table with a speed of

2.0 m s–1. It collides with a stationary trolley also of mass 4.0 kg.

Which of the following diagrams shows a possible outcome?

(1)

46. Two objects collide inelastically. For this system of two objects

A. only momentum is conserved.

B. only kinetic energy is conserved.

C. both momentum and kinetic energy are conserved.

D. neither momentum nor kinetic energy are conserved. (1)

47. Linear motion

(a) Define the term acceleration.

................................................................................................................................... (2)

(b) An object has an initial speed u and an acceleration a. After time t, its speed is v and it has moved through a distance s.

The motion of the object may be summarized by the equations

v = u + at,

s =

4.0kg 4.0kg

2.0ms–1

2.0ms–1

2.0ms–1

2.0ms–10.0ms–1

0.0ms–1

0.0ms–1

4.0kg

4.0kg

4.0kg

4.0kg

4.0kg

4.0kg

4.0kg

4.0kg

A. B.

C. D.

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1. joseph runs along a long straight track. the variation … test review – topic 2: mechanics...

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