Download Impulse and Change In Momentum

Name: ____________________________________________ Period: ___
“Impulse and Change In Momentum”
Show how Newton’s 2nd Law can be rearranged to make a new equation:
This equation is called the “___________________________________”, but it really should be called
the “___________________________________________________”.
IMPULSE is the product of a ___________ and the ____________________ over which it acts.
impulse =
A CHANGE IN MOMENTUM is simply the difference between ______________________________.
change in momentum =
Problems:
1. An 8 N force acts on a 5 kg object for 3 sec.
(a) What impulse is given the object?
(b) What change in momentum does this impulse cause?
(c) If the object’s initial velocity was 25 m/s, then what is its final velocity?
2. A 20,000 N truck is acted upon by a force that decreases its speed from 10 m/s to 5 m/s in 5 sec.
What is the magnitude of the force?
3. A bullet has a mass of 0.02 kg. Starting from rest, after a gun’s trigger is pulled, a constant force
acts on the bullet for the next 0.025 seconds until the bullet leaves the barrel of the gun with a
speed of 1100 m/s.
(a) What is the change in momentum of the bullet?
(b) What is the average force exerted on the bullet while the gun is firing?
4. Suppose a car weighs 16,500 N, and its brakes can apply a maximum force of 560 N to stop it.
The car is initially moving at a speed of 32 m/s and comes to a complete stop.
(a) What is the car’s mass?
(b) What is the car’s initial momentum?
(c) What is the change in the car’s momentum?
(d) How much time did it take the car to stop?
5. Suppose a boy and his skateboard together weigh 670 N. He starts from rest and uses one foot
to “push off” the ground to gain speed up to 2.4 m/s. The time he used to “push off” is 0.72 sec.
(a) What is the combined mass of the boy with the skateboard?
(b) What is their initial momentum?
(c) What is their change in momentum?
(d) What is the average force used by the boy’s leg during the “push off”?
4. A 26.0-g arrow leaves a bowstring at a velocity of 46 m/s.
a. What is the change in momentum of the arrow?
b. What is the average force that the string exerts on the arrow if the string is in contact with
the arrow for 6.0 x 10-3 seconds?