Find the work done by friction and force

[DMB90]

Homework Statement

A box is dragged along the horizontal surface by the applied force Fa (40N) at a 35 degree angle. It moves 7m in 35 sec. What is the work being done by Fa (force), f (friction)?

What is the average power provided by Fa alone during this time?

If speed is not constant what is the instantaneous power provided by Fa when the box is sliding at .25 m/s?

Homework Equations

W= fd cos O?

The Attempt at a Solution