Hope this would help. :)

1. Changing an Object’s
Momentum

2. When will the momentum changes?
 If the mass and/or velocity of an object changes, the
momentum of an object changes.

3. Using Newton’s 2nd Law of Motion
F=ma
F= m(v/t)
F= mv/t
F= p/t
Ft= p Impulse-Momentum
Ft= m(Vf-Vi) Theorem

4. Impulse-Momentum Theorem
 This theorem states that the net external force
applied to an object for a certain time will cause a
change in object’s momentum equal to the product
of force and time interval.

5. Impulse
 I=Ft
 I=mv
 I=p
 Therefore, the unit of impulse is the same as the
momentum which is kg m/s.

6. Sample problems:
1. The 1.5kg ball gains a speed of 95m/s when Gary hits it. What
impulse does he impart to the ball?
2. A 55kg boy is driving his car at a speed of 20m/s. He sees an
old woman crossing the road so he steps on the brake to avoid
hitting the woman. His seatbelt brings his body to a stop at
0.5s. What is the average force does the seatbelt exert on him?

7. Answers
1. Given:
m= 1.5kg
v= 95m/s
Solution:
I= mv
I= 1.5(95)
I= 142.50 kg m/s

8. 2. Given:
m= 55kg
v= 20m/s
t= 0.50s
Solution:
Fnet= mv/t
Fnet= {55(20)}/0.5
Fnet= 2200N

9. Seatwork1
Solve the following problems. Show the complete solution and write
the given.
1. If Lea imparts a 56kg m/s impulse on a 3kg ball, how fast does the
ball moves?
2. A boy is driving his car at a speed of 35m/s. He sees an old woman
crossing the road so he steps on the brake to avoid hitting the
woman. His seatbelt brings his body to a stop at 1s and exerted a
3600 N force to him. What is the mass of the boy?