Question

A tennis ball is thrown vertically upward with an initial velocity of +1.6 m/s. What will the ball's speed after 2 s?
A -23 m/s
B -10 m/s
C -18 m/s
D -9 m/s

Answer 1

Answer: C -18 m/s

Explanation:

This problem is related to vertical motion and the equation that is useful for this situation is:

$V=V_{o}-gt$

Where:

$V$ is the final velocity of the tennis ball at 2 s

$V_{o}=1.6 m/s$ is the initial velocity of the tennis ball (directed upwards)

$t=2s$ is the time

$g=9.8 m/s^{2}$ is the constant acceleration due to gravity

$V=1.6 m/s-(9.8 m/s^{2})(2 s)$

$V=-18 m/s$ This is the final velocity of the ball at $t=2s$ (directed downwards)