a horizontal force of 200 Newtons is applied to a 55 kg cart across a 10 meter surface. If the cart accelerates at 2 meters/second squared, then what is the work done by the force of friction as it acts to retard the motion of the cart ?? Work= FX work= maX 55 kg x 2 x 10 = 1100 - 200 N = 900 Joules ??