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 somone 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.)

 

[m2003]

Your calculations for work output and input are correct. However, to find the efficiency of an inclined plane, you need to divide the work output by the work input, not the other way around. This gives you an efficiency of 97.8%, which means that 97.8% of the input energy was used to lift the motorcycle.

For mechanical advantage, you need to divide the output force (2250N) by the input force (345N), which gives you a mechanical advantage of 6.5. This means that with the use of the inclined plane, Samantha only needed to exert 1/6.5 of the force she would have needed to lift the motorcycle directly.

Additionally, it would be helpful to include the equation for efficiency, which is Efficiency = (Work output / Work input) x 100%. This will make your solution more clear and complete.