Linear Momentum Practice Questions

Updated on Sep 26, 2011

Review these concepts at: Linear Momentum Study Guide

Practice Questions

  1. Does a larger mass necessarily mean a larger momentum? Explain briefly.
  2. In what conditions can an object have zero momentum? Explain briefly.
  3. Can an object have negative momentum? Explain briefly.
  1. What is the connection between the unit for impulse and for momentum?
  2. Are impulse and force measuring the same quantity? Explain briefly.
  3. Does a large force always produce a large impulse? Explain briefly.
  4. Consider the time dependence for a force such as the one in Figure 6.2. Based on the data given, estimate the impulse.

Linear Momentum

  1. If you are to receive a hit from a ball, would you rather make it last a longer or a shorter time?
  2. Why do some brittle objects break when they hit a hard floor but survive a fall on a carpeted floor? Explain briefly.
  3. Is it correct to say that momentum and impulse measure the same quantity? Explain briefly.
  4. In which case is the impulse greater: when an object slows down to half of the speed or when it stops completely? Explain briefly.
  5. Is it possible for an object to move and have zero impulse? Explain briefly.
  6. A car comes to a complete stop in 15 seconds. Consider the mass of the car to be 1,500 kg and the initial speed to be 18 m/s. Find the average breaking force.
  1. What difference in the conservation of momentum does it make that the momentum is a vector quantity? Explain briefly.
  2. Can you have three objects moving and have the total momentum of the three-body system zero? Explain briefly.
  3. In the previous example with the rollerblades, how can you start moving without stepping down (remember, you are holding the ball in your arms)? Explain briefly.
  4. Would it help more if the ball was a medicinal ball, say of mass 10 kg, rather than a soccer ball that you can throw at the same speed? Why or why not?
  1. A ball suffers a horizontal collision with a (non-moving) wall. Are the vector interpretations of momentum and impulse important in this case? Why or why not?
  2. Two identical objects, 1 and 2, headed in the same direction collide perfectly elastically. After the collision, object 1 comes to a rest. Compare the velocity of object 2 after the collision with that of object 1 before the collision (is it equal, larger, smaller?).
  3. Two equal-mass atomic particles move in the same direction with speed v1 and v2. One catches up with the second, and they collide perfectly inelastically. What is the speed of the system after the collision compared to before the collision as a function of v1 and v2?
  4. A small piece of clay is thrown at a moving bike, and the clay sticks to the bike. What happens to the speed of the bike if the mass of the clay is much smaller than the mass of the bike?
  1. A firecracker set on the ground splits into two pieces of equal sizes that spread in two opposite directions. How do the speeds of the two pieces compare?
  2. In practice problem 22, how do the velocities compare? Why?
  3. Two cars approaching from different directions (say east and north) collide. Is it possible for the momentum to be zero immediately after collision? Explain.
  4. What if the cars in practice problem 24 collide head on? Is it possible for the momentum to be zero immediately after the collision? Explain.
  5. Consider again the firecracker in practice problem 22, but in this case moving upward in the NW direction with a speed of 15 m/s. If the mass of the firecracker is 800 g and it splits in three pieces of mass m3 = 2 · m2 = 10 · m1 with the second piece flying after collision in the west direction at 10 m/s, and the third piece flying north at 12 m/s, find the x and y component of the velocity for the first piece.
  6. Write each velocity in practice problem 26 as a vector quantity. Use both the component form with (ax,ay) and the value + angle form.
  7. What is the mass of each of the three pieces in practice problem 24?
View Full Article
Add your own comment