# Projectile motion on inclined plane

1. Oct 19, 2016

### songoku

1. The problem statement, all variables and given/known data
As shown in the figure below, small object A is projected upward along a smooth slope forming angle α with the horizontal plane, with initial speed v0 in the direction of angle θ from the horizontal within the slope’s plane. The object continues to travel along the surface of the slope. Let us denote as h the maximum height that A attains on the slope, where height is measured vertically from A’s starting point. Find v0

2. Relevant equations
projectile motion

3. The attempt at a solution
I interpret the question as projectile motion with total angle (α + θ) with respect to horizontal plane.

At maximum height, vertical speed is zero, so:
vy2 = voy2 - 2gh

v0 = √(2gh) / (sin (α + θ))

But the answer is v0 = √(2gh) / (sin θ)

Do I interpret the question wrongly? Or there is mistake in my working?

Last edited: Oct 19, 2016
2. Oct 19, 2016

### CWatters

The angles don't add in the way you think.

3. Oct 19, 2016

### arpon

You misinterpreted the question. The ball moves "within" the slopes plane, I mean, it does not go "above" the plane.

4. Oct 19, 2016

### songoku

I get the hint. Thanks a lot

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