# Homework Help: Work Problem: Up a ramp

1. Oct 14, 2009

### ddn87

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

Moving a 150kg fridge a 12m ramp with a rise of 2.4m. the mover pulls the ridge up with a constant force of 710 N. the acceleration due to gravity is 9.8 m/s^2

2. Relevant equations

W=Fs
F=ma

3. The attempt at a solution

I found out the angle of the ramp was by doing arcsin(2.4/12)= 11.536959 degrees
So im trying to figure out which forces to split into two components using this angle.

which then i will plug into w=Fs

i set the x and y direction as the direction of the ramp so I split the force of gravity into two components.

i took 710N- Fg)x= Fnet
so i did 710-mgsin(11.536959)=416 N
then i multiplied that number by 12
and got 4992

is this correct if not can you lead me in the right direction

2. Oct 14, 2009

### caitlincui

If you are trying to find the work done, I think it's right if I understand the question correctly.

3. Oct 14, 2009

### ddn87

I got that answer wrong is there a component im forgetting?

4. Oct 14, 2009

### caitlincui

There is also a potential energy. which is work (potential)=mgh=150*9.8*2.4=3528
I think work=Kinetic Energy+Potential Energy=3528+4992=8520

5. Oct 14, 2009

### ddn87

hmmm but the question asks... how much work does HE perform.

6. Oct 14, 2009

### caitlincui

What is HE? Sorry, not a native speaker

7. Oct 14, 2009

### ddn87

by He i mean..... how much work does the person who pulls the fridge up the ramp do?

8. Oct 14, 2009

### caitlincui

Yeah, he does work by performing kinetic energy to the fridge as well as pulling the fridge up 2.4 meters (vertically).

9. Oct 14, 2009

### ddn87

so does mean i should add the PE to 4992N?

10. Oct 14, 2009

### caitlincui

I think so. If I am wrong, then I am sorry... I am interested in finding out the answer.

11. Oct 14, 2009

### ddn87

i only have two more tries left for this problem, thankyou for your help though. i think im going to my study TA tomorrow.