*[ Physics ]* Three pulleys are to be used to lift a 1000N load from the ground to the top floor of a building 40.0m high. Draw an arrangement of the pulleys showing the windings . Given that the efficiency of the machine is 72.0% , calculate the :

1. Velocity ratio
2. Effort required
3. The total energy not used for any useful work. Suggest reasons why there must be loses in energy for this kind of machine.

Suppose you have a box. which of these is not necessarily a true statement regarding the relationship between the force applied to the box, the work done on the box, and the distance the box is moved? a. if the box is not moved, no force is being applied to the box. b. if no force is applied to the box, no work is done on the box. c. if work is done on the box, then a force is applied to the box. d. if work is done on the box, then the box is moved a distance.