Answer:
66.94N
Explanation:
To find the force you use the second Newton law, which is given by:
[tex]F=ma[/tex] (1)
m: mass of the ball 5.85g
the acceleration is:
[tex]a=\frac{v_f-v_o}{t}[/tex]
vf: final velocity = 128mph = 57.21m/s
vo : initial velocity = 0m/s
t: time = 5ms =5*10^{-3}s
by computing the acceleration and replacing it in the equation (1) you obtain:
[tex]a=\frac{57.21m/s}{5*10^{-3}s}=11443.2\frac{m}{s^2}\\\\F=(5.85*10^{-3}kg)(11443.20m/s^2)=66.94N[/tex]
hence, the force applied by Serena on the ball is 66.94N