Buggé/Sierzega/Wilson: Momentum 4
Impulse and Momentum
Did you know?
Impulse
Due to the external force exerted over a specified time interval, an impulse causes a change in
momentum.
I = F∆t
The units for Impulse are N*s.
1. A tennis player hitting a backhand shot exerts a force of 14 N on the tennis ball for 0.15 s.
What impulse is given to the ball?
2. A hockey player takes a slap shot, exerting a constant force of 30.0 N on the hockey puck for
0.16 s. What is the impulse given to the puck?
3. Explain in terms of impulse and momentum, the difference between jumping from a height
and landing in a net versus landing on concrete. Use sketches, bar charts, and force diagrams
to explain your answer.
Buggé/Sierzega/Wilson: Momentum 4
4. Dan strikes a 0.058 kg golf ball with a force of 272 N and gives it a velocity of 62 m/s. How
long was Dan’s club in contact with the ball?
5. In a ballistics test at the police department, Officer John fires a 0.006 kg bullet at 350 m/s into
a container that stops it in 0.0018 s. What is the average force that stops the bullet?
Buggé/Sierzega/Wilson: Momentum 4
6. A basketball player drops a 0.60-kg basketball vertically so that it is traveling at 6.5 m/s when
it reaches the floor. The ball rebounds upward at a speed of 4.2 m/s. Determine the average
force that the floor exerts on the ball if the collision lasts 0.13 s.
Sketch the process before the collision. Sketch the process after the collision. List the given quantities and label them in your pictures. Solve for the momentum of the basketball before and after the collision. Construct a momentum bar chart. Below the bar chart, write the conservation equation and solve. Before 0
Change After Buggé/Sierzega/Wilson: Momentum 4
7.
Stop that bowling ball!
You are under “inception” and a giant 10 kg bowling ball is rolling down the hallway at 8 m/s!
Mr. Wilson comes to the rescue as he courageously stands between the bowling ball and the
children who are about to knocked out like pins!
Now, he needs to decide how to stop the bowling ball and thinks of two options:
1) He can keep his shoes on and stick his arms out to stop it. Considering how strong Mr.
Wilson is, the bowling ball will stop almost immediately.
2) He can take off his shoes, reduce the friction between his socks and the floor and let the
bowling ball still roll for a bit before stopping it completely.
a) What is the change of the momentum of the bowling ball in each case? Remember that
momentum = m·v
1) Before:
After:
∆p:
2) Before:
After:
∆p:
b) In which case do you think would require Mr. Wilson to exert more force on the bowling
ball? Explain your reasoning.