8/3/2019 RECIT for Chapter 8 New Answerkey

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RECITATION QUIZ: Chapter 8

Potential Energy and Energy Conservation

NAME: Date:

SCHEDULE:

INSTRUCTIONS: Choose the BEST answer. Ignore air resistance unless otherwisestated in a question. The magnitude of acceleration due to gravity is 9.81 m/s2.

21. Laminae. The three plates in the figure arehomogeneous, however made from different materials. Themass of each plate is shown in the figure.

A. (-13/7, 8/7)B. (-5/7, -9/7)C. (-1/7, -6/7) Ans :(1, -4/7) BonusD. (5/7, -4/7)E. (15/7, 12/7)

22. Tatsulok I. Three point masses are placed at thevertices of an imaginary triangle. The two point masses at thebase have the same mass, m0, and at the top vertex having a

mass, m. What is the total mass of the system in terms of m0?A.B.C.D.E.

23. Requirements for LCLM. Consider the collision between two particles A and B. Inorder to examine the motion particle A using the law of conservation of momentum, youneed?

I. Examine a system composed of particle A aloneII. Examine of a system composed of particle B aloneIII. Examine of a system composed of particle A and BIV. The sum of the net force on the concerned system is zero

A. I only D. I and IV onlyB. II only E. III and IV onlyC. III only

24. Egg Drop Experiment. An experiment is done to determine the average force of impact needed to break a commercial egg having mass of 50 g. An initially at rest egg isdropped from a height of 0.200 m. As it hits the ground, the egg breaks and the highspeed camera used to capture the scene registers that thetime of contact is between the floor and the egg is 0.015 s.What is the average force of impact for this case?

A. D.B. E. 0C.

25. Ballista. Ballistic pendulum set-up is used to measure the speed of a bullet. A0.00400 Kg bullet is fired horizontally so that it will hit a suspended 3.00-kg woodenblock. After a completely inelastic collision, the block swings likea pendulum and reached a maximum height of 0.0350 m. Whatis the speed of the bullet before it hit the block?

A. 3.87 x 105 m/s D. 8.29 x 10-2 m/sB. 6.22 x 102 m/s E. 8.28 x 10-2 m/s

C. 5.16 x 102 m/s 

8/3/2019 RECIT for Chapter 8 New Answerkey

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RECITATION QUIZ: Chapter 8

Potential Energy and Energy Conservation

NAME: Date:

SCHEDULE:

26. Akyat Manaog. Ball A having a mass of 1.00 kg is releasedfrom rest on a frictionless inclined at a height of 0.500 m abovethe frictionless horizontal plane. After it reached the horizontal

plane, it continued to move and hit a stationary Ball B of mass2.00 kg. After a head on collision it, Ball B gains a speed of 1.5m/s. Ball A recoils and starts to gain height again as it climb theinclined. How much height it can climb?

A. 38 m D. 0.77 mB. 1.9 m E. 0.31 mC. 6.3 m

27. Physics 71.1’s Ramp. Two identicalmarbles, Marble I and Marble II, areplaced on point A and point Brespectively as shown. The elevation of 

point B from the ground, h, is 0.20 m.After the marble is released from rest,Marble I hit Marble II and they got off theramp. Marble I covered a range x1 =0.15m and Marble II covers a range x2 =0.25m before they hit the ground. Fromwhat height Marble I is released?

A. 0.54 m D. 0.27 mB. 0.38 m E. 0.18 mC. 0.29 m Answer : 0.40 m Bonus

For the next two question: Below is a table of different cases of two marblesexperienced a head on collision on a frictionless surface. v1 and v2 are the initial velocitiesof m1 and m2 , and v’ 1 and v’ 2 are the final velocities of m1 and m2.

Case m1 m2 v1 v2  v’ 1 v’ 2 

A 3.00 kg 10.00 kg 5.0 m/s 0 4.0 m/s 0.30 m/s

B 3.00 kg 10.00 kg  5.0 m/s 0 3.0 m/s 0.60 m/s

C 3.00 kg 10.00 kg  5.0 m/s 0 1.0 m/s 1.2 m/s

D 3.00 kg 10.00 kg  5.0 m/s 0 0.00 m/s 1.5 m/s

E 3.00 kg 10.00 kg  5.0 m/s 0 -2.0 m/s 2.1 m/s

28. Momentum Transfer. Which of the following cases momentum transfer mostefficient? E29. Energy Transfer. Which of the following cases marble m1 transfer its energy mosteffective? D

30. Energy Dissipation. Which of the following cases energy dissipation is greatest? C

Partially Elastic Collision. Particle X of mass 2.00 kg and particle Y of mass 3.00 kgare moving in a frictionless plane. Particle X has an initial speed of 12.0 m/s whileParticle Y has an initial speed of 4.00 m/s, both particles initially moving to the right.After sometime, particle X was able to catch up and then had a head on collision withparticle Y. After collision, Particle X’s velocity is 9.00 m/s to the right. How muchmechanical energy is lost because of the collision?

A. 1130 J D. 73.5 JB. 1010 J E. 52.5 JC. 86.8 J