PROBLEM SOLVING COMPLETE SOLUTION
QUESTION
1. A 0.05 kg tennis ball approaches a racket at 25 m/s. If it is not in contact with the
racket's strings for 0.005 s, then rebounds at 25 m/s, what is the average contact
force between the ball and the racket? Ignore air resistance.
2. A 5.0 kg crate initially at rest on a smooth surface is acted upon by two opposing
forces: 50 N to the right and 30 N to the left. Find the acceleration of the block and
the distance it moves in 10 s.
ANSWER
1. F = 500 N
2. a = 4 m/s2
d = 400 m
Explanation
Problem Solving
1. F= mΔv /t
= 0.05(25-(-25)) /0.005
= 2.5/0.005
F = 500 N
2. F1 = 50 N
F2 = 30 N
Fnet = F1-F2
Fnet= 50-30
Fnet = 20 N
a = Fnet/m
= 20 / 5
a = 4 m/s2
v = at
= 4(10)
= 40 m/s
d = vt
= 40(10)
d = 400 m
