Calculating Acceleration and Velocity of a Falling Ball in One Dimension

[Questions999]

A ball is released from the height 3 meters and after it hits the floor it reaches the height 2 meter. A) Whats the speed of the ball in the moment when it meets the ground?
My answer : V^2-V0^2=2gs and here we find V=sqrt60.
What is the speed of the ball in the moment it leaves the ground? V2^2-V^2=2gh2 so V2^2- sqrt60=2g*2 and here we find V2=10
c) If the ball meets the ground for 0.02 seconds what's the direction and numerical value of the acceleration? The direction is upside down and a=(10-sqrt60)/0.02 ARE THESE CORRECT?

 

[tiny-tim]

Hi Elaia06!

(try using the X² button just above the Reply box )

A ball is released from the height 3 meters and after it hits the floor it reaches the height 2 meter. A) Whats the speed of the ball in the moment when it meets the ground?
My answer : V^2-V0^2=2gs and here we find V=sqrt60.

fine

What is the speed of the ball in the moment it leaves the ground? V2^2-V^2=2gh2 so V2^2- sqrt60=2g*2 and here we find V2=10

no, that's a constant acceleration formula, so you can't use it "over the bounce" …

try it with final speed 0 ​

 

[Questions999]

You mean I should correct the third question,not the second one? maybe you did a little mistake over there?

 

[tiny-tim]

no i did mean the second question (What is the speed of the ball in the moment it leaves the ground?)

 

[Questions999]

I attached an image to the reply,it has the formulas for the non constant acceleration..but I don't have the time...