- #1
Liam C
- 57
- 4
Homework Statement
Mariana is volleying with Old Man Miller and returns one of his feeble tennis serves. He serves the ball such that it is moving at a speed of 35km/h [Forward] when she strikes the 0.060kg ball and sends it back over the net at a velocity of 55km/h[Backward].
a) If the ball spends 0.075 seconds in contact with the racquet determine the force acting on the ball.
b) What was the force applied by the ball on the racquet during the stroke?
Homework Equations
Fnet = ma
The Attempt at a Solution
a)
I’m assuming it’s talking about Mariana’s stroke:
V1 = 35/3.6 m/s = 9.72m/s
V2 = -55/3.6 m/s = -15.28m/s
t = 0.075s
m = 0.060kg
a = V2 - V1 / t
a = -15.28 - 9.72 / 0.075
a = -333m/s^2
ΣF = ma
ΣF = (0.060)(-333)
ΣF = -20N
∴ The force acting on the ball was 20N [Backward]
Is it asking for a net force and is that what I provided?
b)
I have no idea how to find the force applied by the ball. If it is horizontal motion then isn’t the motion uniform? How do I find the force of an object moving uniformly? I’d like some help approaching this question.