1. Impulse Momentum Problems Answers
1. A force of 6.00 N acts on a 3.00-kg object for 10.0 s.
(a) What is the object’s change in momentum?
F t = ∆p
F = N t = s
= ( 6.00 N )( 10.0 s )
= ∆p = 60.0 N s
(b) What is its change in velocity?
p = m v
∆p = m ∆v m m ∆p
60.0 N s
∆v = =
Challenge: Show that m
3.00 kg
N s =
m/s kg
∆v = m/s

2. 2. What force is needed to bring a 1500-kg car moving at 22.0 m/s to a
halt in 20.0 s?
p = m v
= ( 1500 kg )( 22.0 m/s)
= kg m/s
pi = kg m/s
pf = 0
∆p = pf - pi
F t = ∆p
= kg m/s t t
∆p = kg m/s ∆p
F = t
kg m/s =
20.0 s
F = N

3. 3. Calculate the momentum of a baseball of mass 0
3. Calculate the momentum of a baseball of mass 0.15 kg when it is traveling at a speed of 46 m/s.
p = m v
= ( 0.15 kg )( 46 m/s )
p = 6.9 kg m/s

4. 4. A car of mass 1000 kg is accelerated from rest at a rate of 3
4. A car of mass 1000 kg is accelerated from rest at a rate of 3.0 m/s2 for
a time of 6.0 s. Calculate its momentum at the end of this time.
p = m v
v = ?
m = kg a = 3.0 m/s t = 6.0 s vi = 0
vf = vi + a t
= ( 3.0 m/s2 )( 6.0 s )
vf = 18 m/s
p = m v
= ( 1000 kg )( 18 m/s )
p = kg m/s

5. 5. A car weighing 15 680 N and moving at 20.0 m/s is
acted upon by a 640 N force until it is brought to a halt.
(a) What is the car’s mass?
Wt. = m g g g
Wt. N
= m = kg
m = = g
9.8 m/s2

6. 5. A car weighing 15 680 N and moving at 20.0 m/s is
acted upon by a 640 N force until it is brought to a halt.
(b) What is its initial momentum?
pi = m vi
= ( 1600 kg )( 20.0 m/s )
pi = kg m/s
(c) What is the change in the car’s momentum?
∆p = pf - pi
pf = 0
= kg m/s
∆p = kg m/s

7. 5. A car weighing 15 680 N and moving at 20.0 m/s is
acted upon by a 640 N force until it is brought to a halt.
(d) How long does the braking force act on the car to bring
it to a halt?
F t = ∆p
F = N (braking force) F F ∆p
kg m/s
kg m/s
t = = = F
- 640 N
- 640 kg m/s2
t = 50 s

8. 6. A tennis ball of mass 55.0 g is traveling towards Bob at 25.0 m/s.
After hitting it, it travels away from Bob at 30.0 m/s.
(a) What is the change in velocity?
m/s
m/s
vi = m/s
vf = m/s
∆v = vf - vi
= ( m/s ) - ( m/s )
∆v = m/s

9. 6. A tennis ball of mass 55.0 g is traveling towards Bob at 25.0 m/s.
After hitting it, it travels away from Bob at 30.0 m/s.
(b) If the ball was in contact with the racket for 0.15 s,
what force did the racket exert on the ball?
∆v = m/s
F t = ∆p
= m ∆v
m = g
= kg t t
m ∆v
( kg )( 55.0 m/s)
F = = t
0.15 s
F = N