PHY2048 - GENERAL PHYSICS I
REVISION QUESTIONS FOR CHAPTER 8

Below you will find a set of 5 conceptual and numerical revision questions selected randomly from lots of questions I have put together covering the material in Chapter 8, "Systems of Particles and Conservation of Momentum". This includes questions on the center of mass, conservation of momentum, kinetic energy, collisions and impulse. When you have finished the quiz, click on the "Submit Quiz" button at the bottom and within seconds it will be automatically graded and the results returned to you!

To select a new set of questions click on the "Reload" or "Refresh" button on your browser. You may find some of the questions duplicated but that's the nature of a random selection. Try it a few times ... it's not fattening and you may learn something!

Many thanks to Mark Wood for producing the quiz-maker code.


Q1: The earth has mass 5.89 ¥ 1024 kg. The moon has mass 7.36 ¥ 1022 kg and is 3.84 ¥ 105 km from the earth. How far from the center of the earth is the center of mass of the earth‹moon system?

4.7 ¥ 103 km
7.4 ¥ 103 km
1.9 ¥ 105 km
2.1 ¥ 105 km
3.8 ¥ 103 km

Q2: A car of mass 3.0 ¥ 103 kg traveling at a speed of 20 m/s is passing a truck of mass 7.5 ¥ 103 kg traveling at a speed of 16 m/s in the same direction. What is the speed of the center of mass of this system?

16 m/s
17 m/s
18 m/s
19 m/s
20 m/s

Q3: A car having a total mass of 2250 kg and traveling at 72.0 km/h smashes into a tree. The car is stopped in 0.250 s. The average force acting on the car during the collision is

1.80 ¥ 105 N
80.0 N
1.80 ¥ 102 N
2.20 ¥ 105 N
2.20 ¥ 104 N

Q4: An automatic rifle fires 0.040 kg bullets at a speed of 800 m/s. If the gunner holding the rifle in her hands can exert an average force of 160 N against the gun, the maximum number of bullets she can fire in one minute is

15
300
800
4000
48,000

Q5: A body is acted on by an impulsive force from time t = 0 to time t = 10 ms. During this time, the force decreases uniformly from 103 N to zero as shown in the graph below.

What is the change in momentum of the body during this interval?

10 kg.m/s
5.0 kg.m/s
0.16 kg.m/s
105 kg.m/s
2.5 kg.m/s


Click on the Submit Quiz button below to have your quiz automatically graded.

Please note that you may be able to use the "Back" and "Forward" buttons on your browser to check the answers with the questions.