Magnitude done by Kinetic Friction-Have answer need help getting there.

Question

A box weighing 12 N has an initial speed of 2.1 m/s. As it slides across

a level floor it comes to a stop in 3.2 m due to kinetic friction. What is the magnitude

of the work done by the kinetic friction force acting on the box?

Answer: 2.7 J

Answer 1

You should use the Work-Energy Theorem:

W = ΔE

In this case, the work is done by the Force of friction over a distance that is given. W = F⋅d

The result is a change in the kinetic energy. KE =. 1/2 mv² .

This is all you need to solve for.

But, be careful, the "weight" of the box is given, you have to solve for its mass.