A 1.21 kg block slides down a 25.0 m long 25.0° incline at constant velocity. How much work is done by friction?

3 answers

work= force dot distance= mg*15.0*cos 25
Where is the 15 coming from? I thought that you may have meant 25 so I calculated 1.21*9.8*25*cos 25 and I got the answer wrong.
Yea, I was wondering the same thing because mine is wrong too!