# Homework Help: Finding acceleration when there is friction and force is applied at an angle to horizontal

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1. Oct 5, 2014

### Evan Johnson

1. The problem statement, all variables and given/known data
Sheldon moves a box of comic books to stuarts comic book store by attaching a rope to the box and pulling with a force of 90 N at an angle of 30. The box of comic books has a mass of 20 kg and the coefficient of kinetic friction between the bottom of the box and the sidewalk is .5. Find the acceleration of the box

2. Relevant equations
F=ma

3. The attempt at a solution
i know the answer is A=.12 m/s^2 but i have no idea how to get to that answer, please explain!!

2. Oct 5, 2014

### phinds

Draw the force vectors. You have not even started to solve such a problem until you have drawn the force vectors.

3. Oct 5, 2014

### Evan Johnson

i did i drew a fbd

4. Oct 5, 2014

### Evan Johnson

and i think its Facos(30) for x axis and Fasin(30) for y axis

5. Oct 5, 2014

### phinds

I say again, draw the force vector diagram (and show it here).

6. Oct 5, 2014

### Evan Johnson

I actually just figured it out!! :) but thanks for your help anyways!!