A truck pulls boxes up an incline plane. The truck can exert a maximum force of 2,400N. If the plane's incline is 2π3 and the coefficient of friction is 53, what is the maximum mass that can be pulled up at one time?

1 Answer
May 10, 2018

The truck will be able to pull up to 144 kg.

Explanation:

This calculation is neglecting any friction or gravity acting on the truck, so it's net force is 2400 N up the slope. Also, I'll take theta as π3 or 60˚. This is because 2π3 is 120˚ and takes you beyond a vertical slope and back around to 60˚.

The parallel component of the gravitational force on the box is given by

Fg=mgsin(θ)

This is the force that gravity exerts on the box down the slope.

The normal force acting on the box is given by the perpendicular component of the gravitational force

N=mgcos(θ)

The frictional force is then given by

Ff=μsN=μsmgcos(θ)

Fg and Ff are the opposing forces so if we set the sum of these equal to 2400 N, that will allow us to solve for the maximum mass

Fg+Ff=2400

mgsin(θ)+μsmgcos(θ)=2400

m(gsin(θ)+μsgcos(θ))=2400

m=2400gsin(θ)+μsgcos(θ)

m=24008.487+8.167=144 kg

Where

g=9.80 m/s

μs=53

θ=π3