Question

What’s the force of a pitching machine on a baseball? Baseballs pitched by a machine have a horizontal velocity of 30 meters/second. The machine accelerates the baseball from 0 meters/second to 30 meters/second in 0.5 seconds. If a baseball has a mass of 0.15 kilograms, the force the machine exerts is newtons. Use F = ma, where  .

Answer 1

The acceleration of the baseball is:
$a= \frac{v_f-v_i}{\Delta t}$
where $v_f$ and $v_i$ are the final and initial speed of the ball, and $\Delta t$ is the time interval in which the force acted.

Replacing the numbers, we get
$a= \frac{30 m/s-0m/s}{0.5 s}=60 m/s^2$
And at this point, we can use Newton's second law F=ma to find the value of the force of the pitching machine:
$F=ma=(0.15 kg)(60 m/s^2)=9 N$