physics
posted by Jacob .
A box is pulled across a horizontal surface at a constant speed by a horizontal rope with tension T=30N. The coefficient of friction between the box and surface is uk = 0.05.
1. Calculate the work done by friction as the box moves 4 meters to the right.
i thought it would be .05 x 30 x 4 since work is F x D but it isn't
2. What is the mass of the box.

Multiply pulling force by distance for the work done.
Use the uk value to get the mass of the boss.
Friction force = M*g*uk