# Tilted FBD Forces Problem

1. Nov 29, 2009

### ccmetz2020

1. The problem statement, all variables and given/known data
A sled weighing 100 N is held in place on a frictionless 20 degree slope by a rope attached to a stake at the top. The rope is parallel to the slope. Use the FBD diagram of the sled below to answer the following. What is the correct formula in both the x and y direction? (referring to F=ma and F=0, newton's 1st and 2nd laws). What is the normal force of the slope acting on the sled? (HINT: the force of weight is at an angle to your tilted coordinate system and needs to be broken down into its x and y components.)

I have attached the given FBD to this post

2. Relevant equations
Fy=0
Fx=0???

3. The attempt at a solution
In the y direction:
Fy=0 so
n - Wy = 0
In order to find Wy, I formed a right triangle with the 20 degree angle and used calculated that -100sin20 = approx. -34 N
That makes n = +34 N, right?
In the x direction:
That would mean: T-Wx = 0 right?
In the problem, it does not state to find what tension equals so I think all I had to do was write the correct formula in the x direction. Does this look good to you guys? Thanks.

#### Attached Files:

• ###### untitled.bmp
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2. Nov 30, 2009

### kjohnson

It is correct except to find wy it would be 100*cos(20) since the angle is measured relative to the verticle. Likewise wx would be caculated using the sine function.