friction force stops a book that slides 20 cm across a tabletop. (c) A child is held 80 cm above the floor by a 150-N force. (d) A car jack exerts a force of 5000 N on a car and lifts it 20 cm. (e) A car jack exerts a force of 5000 N on a car as lowered 20 cm.I seriously need some help on how you set this problem up.
W work done F x displacement(along line of action of F) i) W 50 N x 0.30 m 15 Joules ii) d -0.20 m (opposite direction to the frictional force) W F x (d) 50 (-0.2) -10 J iii) d 0 W Fx0 0 iv) 5000 x 0.20 1000 J v) the car jack force is a restraining force opposite the displacement direction W - 5000 x .20 -1000 J hope this helps
