Physics A: Problem Set 23: Impulse and momentum
recommended reading
High Marks: | 1:117–1:121 |
Barron's Let's Review: | 6.1–6.2 Newton's Second Law and Momentum |
physics.info: | Impulse & Momentum |
Wikipedia: | Impulse, Momentum |
HyperPhysics: | Impulse of force, Momentum |
Khan Academy: | Impacts and linear momentum |
Mr. Machado: | 06 Momentum, 10 Introduction to impulse, 11 Impulse - Solving for net force |
definition of momentum
- Read the following excerpt of an interview with the American amateur naturalist Timothy Treadwell.
Now, the bears I live with average, the males, eight to twelve hundred pounds [360 to 540 kg]. They're the largest bears in the world…. They've been clocked at 41 [mph] and they've run a hundred meter dash in 5.85 seconds, which a human on steroids doesn't even approach.
- Compute the speed of a grizzly bear using Mr. Treadwell's hundred meter statement.
- Compute the momentum of a grizzly bear using the speed you calculated in part a. and the average mass stated by Mr. Treadwell.
- How fast would a 250 lb man have to run to have the same momentum you calculated in part b? (Do not use a calculator to compute your answer.)
- How fast would a 4000 lb car have to drive to have the same momentum you calculated in part b? (Do not use a calculator to compute your answer.)
impulse-momentum theorem
- A falling rubber ball of mass 0.025 kg strikes the ground traveling straight down at 4.0 m/s. Find the magnitude of the impulse that the ground gives to the ball if…
- the ground is soft and the ball stops dead
- the ground is hard and the ball bounces straight up at 2.0 m/s
- What is the basic idea behind crash safety features in cars like seatbelts, airbags, crumple zones, etc. What quantities in the impulse-momentum theorem (F∆t = m∆v) change as a result of these features, how are they changed, and how does this result in increased safety during a crash?