A small body of mass m is located on a horizontal plane at the point O. The body acquires a horizontal velocity v_(0). Find the mean power developed by the friction force during the whole time of motion, if the frictional coefficient mu = 0.27 m = 1.0 kg and v_(0) 1.5 m//s.

A small body of mass m is located on a horizontal plane at the point O

1.	A small body of mass m is located on a horizontal plane at the point O. The body acquires a horizontal velocity v_(0). Find the mean power developed by the friction force during the whole time of motion, if the frictional coefficient mu = 0.27 m = 1.0 kg and v_(0) 1.5 m//s.
Answer» SOLUTION :Work done against the frictional force W `= - mu mgs` ` therefore (dW)/(dt) = - mu mg((ds)/(dt)) or P = - mu mgvlt P GT= (int_(0)^(v_(0)) Pdv)/(int_(0)^(v_(0))dv) = (int_(0)^(v_(0))-mu mg v dv)/(int_(0)^(v_(0)) dv)` SOLVING, we get ` lt P gt = (-mu m g v_(0))/(2)` Substituting the given values, we get ` lt P gt = - (0.27 xx 1 xx 9.8 xx 1.5)/(2) = -2` Watt.