# Ball bounces several times on an inclined plane

carlyn medona

## Homework Statement

A ball falls on an inclined plane of inclination theta from a
height h above the point of impact and makes a perfectly
elastic collision. Where will it hit the plane again ?
Solve the previous problem if the coefficient of restitution
is e. Use theta = 45°, e = .75 and h = 5 m.

## The Attempt at a Solution

I was able to solve first part of the problem and got the distance along the incline to be =8hsinθ. For second part I am getting angle of reflection of ball with normal to be 53 degree but the value in my text is 37degree. but I dont think the angle should be less than theta

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perfectly elastic collision
coefficient of restitution is e.
e = 0.75
So is it perfectly elastic or not?

CWatters
Homework Helper
Gold Member
So is it perfectly elastic or not?
They want it solved twice. Once perfectly elastic then again with e=0.75.

carlyn medona
that's right. In second case it is not elatic

haruspex
Homework Helper
Gold Member
angle of reflection of ball with normal to be 53 degree but the value in my text is 37degree. but I dont think the angle should be less than theta
You are correct. If e < 1 then the angle to the normal of the reflection will be greater than the incident angle to the normal.
I assume you noticed that 37=90-53.

carlyn medona
yes.

carlyn medona
okay i finally solved it and got a value of 18.5 m along the incline, thanks for the help.

haruspex