# Block on Incline

1. Jan 31, 2009

### shikamarufoo

1. The problem statement, all variables and given/known data

A 725 gm block slides down an inclined plane that makes an angle of 30° with the horizontal. It accelerates at 1.5 m/s2.

a) Find the magnitude and direction of the total force exerted on the block by the plane. For the direction, give the angle as measured counterclockwise from the vertical (in degrees).

b)What are the magnitude and direction of the force exerted on the plane by the block? For the direction, give the angle as measured counterclockwise from the vertical (in degrees).

I figured out the force of Friction was 2465

2. Relevant equations
fnet = ma
Not really sure on what other equations to use

3. The attempt at a solution

For a) I tried drawing a fbd and making a a triangle to find the hypotenuse to get the magnitude of the normal force, but I'm not getting it right. I also did sqrt(NormalForce^2 + Friction^2). For b), I'm not sure where to start.

Could you please walk me through this because I'm a bit confused now. Thanks~
Can someone please walk me through this because I'm a bit confused.

2. Feb 1, 2009

### Delphi51

Probably on the right track, but did you remember to convert the grams to kg?
I don't think you need this force because it is part of the plane on box force you are trying to find.

This is an unusual question! Back to basics, I think.
Sum of the forces on the box = ma.
Gravity force + force of plane on box = ma

It is 2D so you need to work with two perpendicular directions. You could do it with horizontal and vertical directions or go with along the plane and into the plane.