Originally posted by AThousandYoung
You should offer up the problem.
Are you trying to determine power as a function of time given that you know the force as a function of time?
a crate has a mass of 210 kg and rests on a(horizontal) surface for which the coefficients of static "s", and kinetic friction"k" are 0.4 & 0.3 respectivley
If the motor M supplies a cable force of F = (8t^2 + 20)N , where t is in seconds, determine the power output developed by the motor when t = 7 s.
This part you'll have to take my word
let +x axis be to the left
3T to the left (because of mechanical advantage of pulleys) and Friction force to right.
sum Fy is not needed except for detrermination of Friction force which is just c(Fw)
c stands for coefficient, and Fw force weight.
there it is.