You want to push a 66-kg box up a 30° ramp. The coefficient of kinetic friction between the ramp and the box is 0.35. With what magnitude force parallel to the ramp should you push on the box so that it moves up the ramp at a constant speed?

Question

You want to push a 66-kg box up a 30° ramp. The coefficient of kinetic friction between the ramp and the box is 0.35. With what magnitude force parallel to the ramp should you push on the box so that it moves up the ramp at a constant speed?
N

Physics - bobpursley, Thursday, February 16, 2012 at 5:04pm

You have to overcome friction and gravity

gravity down the plane:mg*SinTheta
friction: mg*mu*cosTheta

I know i posted this before earlier sorry about that but I really need help with it because its not working out please help

yoyoma · Answer

Hello! You have the correct formula: F= mgsin theta

Now plug in those values!

m=66 kg
g= 9.8 m/s^2
theta (angle)= 30 degrees

Normal Force= 66 * 9.8 * 0.5
Normal Force= 33 * 9.8
Normal Force= 323.4 Newtons

Then, use F=coefficient of friction * Normal Force

F= 0.35 * 323.4
F=113.19 Newtons which rounds to 113.2 N

Hope this helps!