Answer:
F=248.5W N
Explanation:
Newton's 2nd Law tells us that F=ma. We will use their averages always. The average acceleration the tennis ball experimented is, by definition:
[tex]a=\frac{\Delta x}{\Delta t}=\frac{v-v_0}{t-t_0}[/tex]
Since we start counting at 0s and the ball departs from rest, this is just [tex]a=\frac{v}{t}[/tex]
So we can write:
[tex]F=ma=\frac{mv}{t}=\frac{gmv}{gt}[/tex]
Where in the last step we have just multiplied and divided by g, the acceleration of gravity. This allows us to introduce the weight of the ball W since W=gm, so we have:
[tex]F=\frac{Wv}{gt}=\frac{v}{gt}W[/tex]
Substituting our values:
[tex]F=\frac{(73.14m/s)}{(9.81m/s^2)(30\times10^{-3}s)}W=248.5W N[/tex]
Where the average force exerted has been written it terms of the tennis ball's weight W.
