# A 6kg box is placed on a 32degree frictionless ramp. Find accel. of the box.

1. Sep 29, 2009

### Kaxa2000

I have the solution to the problem but I don't get the part how you rotate the axes and then solve from there.

For example in the x direction
Fx = max

+mg sin32 = max

Fx = Force in x direction
ax = acceleration in the x direction

Can someone explain this?

2. Sep 30, 2009

### Kurdt

Staff Emeritus
You're taking the component of the weight vector down the ramp. That is the force that accelerates the box.

3. Sep 30, 2009

### tiny-tim

Welcome to PF!

Hi Kaxa2000! Welcome to PF!
I'll just add that you shouldn't think of it as a rotation …

everything stays as it is, and you simply choose to take components in whatever direction is most convenient

for example, you could use horizontal and vertical components …

but that would give you two equations , while choosing along-the-ramp and normal gives you only one relevant equation, which is much easier!

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