Question

How high should you be if you want to drop a tennis ball and have it hit the ground with a velocity of -25.0 mi/hr?

Answer 1

Data: Final velocity = 11.176m/s (or 25 mi/hr)

Firstly, we need to replace our values on the third given equation. It is convenient to use all the values on their SI units.

`11.176^2=0^2-2*9.81*\Delta x\Rightarrow\Delta x=(11.176^2)/(-2*9.81)=-6.366m`

Thus, the ball would need to be dropped from a height of 6.366m, or 20.89ft