Figuring out the efficiency of an inclined plane

[simplekin]

Homework Statement

Rather than lifting a 225kg motorcycle 60cm on a truck, Samantha uses a 4m plank as an incline and only requires 345N to push up the ramp

Homework Equations

The Attempt at a Solution

To find work output, i did .6M X 2250N giving me 1350 J
To find work input, i did 345N X 4M giving me 1380J
I divided 1350J by 1380J giving me 97.8 % efficiency
For mechanical advantage i said 6.5, by dividing 2250N by 345N



Can someone correct this, or tell me if I got this right, thank you!

 

[Doc Al]

Looks OK to me. (You are using a value of g = 10 m/s^2.)