Ball thrown upwards: Acceleration and Velocity

[helloimsam]

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

1. Homework Statement
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.

Homework Equations

velocity = displacement/time
acceleration = velocity/time
force = mass x acceleration

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!

 

[SteamKing]

What goes up must come down.

What happens to the ball when it stops going up?