Question

A small rubber ball is launched by a compressed-air cannon from ground level with an initial speed of 17.3 m/s directly upward. Choose upward as the positive direction in your analysis. (a) What is the maximum height above the ground that the ball reaches?

Answer 1

Answer:

h=15.27m

Explanation:

Since at maximum height the vertical velocity must be null it's better to use the formula:

$v_f^2=v_i^2+2ad$

We will use this formula for the vertical direction, choosing the upward direction as the positive one, so we have:

$0=v_i^2+2ah$

or

$h=-\frac{v_i^2}{2a}$

which for our values is:

$h=-\frac{(17.3m/s)^2}{2(-9.8m/s^2)}=15.27m$