# What happens when a ball is thrown vertically in the air?

## Homework Statement

A ball is thrown vertically in the air, upward from the surface of the Earth. Which of the following quantities are zero when the ball reaches maximum height?
a)speed b)velocity c)acceleration

## The Attempt at a Solution

i answered just b, but i got it marked wrong so i am unsure. any thoughts?

Doc Al
Mentor

because when the ball reached maximum height, the ball stops and then changes direction, so then it would have v=0 and the top. but would the speed be 0 as well?

Doc Al
Mentor
You tell me. What's the relationship between speed and velocity?

velocity has to have direction while speed does not.

Doc Al
Mentor
velocity has to have direction while speed does not.
Good. Speed is just the magnitude of the velocity. So how would you revise your first answer?

both speed and velocity will be zero?! :)

Doc Al
Mentor
both speed and velocity will be zero?! :)
Of course. thank you so much!!
is there any chance you could also help me with a math problem that is giving me lots of trouble?

Doc Al
Mentor
is there any chance you could also help me with a math problem that is giving me lots of trouble?
Did you post it?

yes but no replies yet,.