Question

A person is pulling a 20kg crate. If the frictional force is 50N, and the crate is accelerating at 2m/s^2, what is the tension in the rope?

Answer 1

The tension in the rope is 90 N.

The person pulls the crate of mass m using a rope. The rope is under a tension T. The ground exerts a force of friction f on the crate.The force of friction is directed opposite to the motion of the crate. The crate accelerates in the direction in which the person pulls with an acceleration a.

Write the force equation for the motion of the crate.

`T-f=ma`

Therefore,

`T=ma+f`

Substitute 20 kg for m, 2m/s² for a and 50 N for f in the equation and calculate T.

`T=ma+f\\ =(20 kg)(2m/s^2)+(50 N)\\ =90N`

The tension in the rope is 90 N