A horizontal force of 120 N is used to push a 49 kg box 5.4 m on a rough, horizontal
surface.
The acceleration of gravity is 9.8 m/s
2.
1) If the box moves at constant speed, find the
work done by the 120 N force.
Answer in units of J.
2) How much energy is lost to friction?
Answer in units of J.
3) What is the coefficient of kinetic friction?

3. a worker pushes a 30.5 kg polished stone along a polished table with a force on bonin a straight line for 5.20 s after starting from rest. there is no friction between thestone and the table. at the end of the table. the stone is hooked to a cable with a lengthof 62.0 cm to rotate it to a rough table to store until they can be picked up. the roughtable has a coefficient of static friction 0.702 with the polished stone. remember that 8= 9.80 m/s2a) what is the speed of the stone when it is hooked to the cable? b) what is the tension in the cable while the stone is rotating? (there is still nofriction)c) how much force is needed to make the stone begin sliding from rest on therough table? ius = 0.70262.0 cm30.5 kg20.5 kg6= 0