A mover's dolly is used to deliver a refriger- ator up a ramp into a house. The refrigerator has a mass of 143 kg. The ramp is 3 m long and rises 0.45 m . The mover pulls the dolly with constant velocity and with a steady force of 535 N up the ramp. The dolly and ramp constitute a machine. The acceleration of gravity is 9.8 m/s2 . What work does the mover do? Answer in units of J.
What gravitational potential energy is gained by the refrigerator?Answer in units of J.
What is the efficiency of the machine? Answer in units of percent.