Question

A tennis ball is thrown upwards with an initial velocity of 5.4 m/s how high does it go?

Answer 1

With the assumption that the acceleration due to gravity is 9.8m/s^2 and that the upwards direction is positive:

We can use the kinematics equation,
`v_f^(2)- v_0^(2)=2aS`, where v is velocity, a is acceleration, and S is displacement. Initial velocity is given as 5.4 m/s. We know final velocity is 0, because we want to know the displacement at the peak of the tennis ball's motion. Acceleration is -9.8m/s^2. Just plug in these values to find the displacement:


`v_f^(2)- v_0^(2)=2aS \\ 0^(2)- 5.4^(2)=2(-9.8)S \\ -29.6=-19.6S \\ S=1.51`

So the tennis ball goes 1.51 meters upwards.