# Homework Help: Ball thrown upwards: Acceleration and Velocity

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1. Oct 11, 2014

### helloimsam

Hello, all! I was searching online for help w/ my Physics hw and I stumbled upon this website. New member here (:

1. The problem statement, all variables and given/known data

A baseball is thrown directly upwards.
a. Is there a point on the trajectory where the ball has zero velocity? Explain.
b. Is there a point on the trajectory where the ball has zero acceleration? Explain.

2. Relevant equations
velocity = displacement/time
acceleration = velocity/time
force = mass x acceleration

3. The attempt at a solution
So I've gotten to the point where I've figured that the velocity is constantly decreasing due to the force of gravity, and that the acceleration is negative and also stays constant. However, I'm really struggling in answering the question pertaining to points of ZERO v/a and putting this in words (that actually make sense). Help would be much appreciated!

Thanks!

2. Oct 11, 2014

### SteamKing

Staff Emeritus
What goes up must come down.

What happens to the ball when it stops going up?