Two blocks travel along a level frictionless surface. Block A is initially moving to the right, while block B is initially at rest. The mass of block A is greater than the mass of block B. The positive x-direction is to the right. The magnitude of the change in momentum of block A is the magnitude of the change in momentum of block B.

Explanation:

The magnitude of the change in momentum of block A is equal and opposite the magnitude of the change in momentum of block B.

According to law of conservation of momentum , there should not be any change in the  momentum in the system  .The system consists of A and B .  So if some change in momentum has occurred in A  , the other must have equal and opposite change in momentum so that they get cancel out and net change in momentum of system is zero.

given data:

determine the horse power (h.p) = ?

force applied to move the box(f) = 10 pounds,

box lifted from a distance         (d) = 3 feet

time taken to lift                         (t) = 10 sec,

the horse power is defined as amount of work required to move a load. the horse power is equal to 550 foot-pound per second

                  1 h.p   = 550 foot-pound/second

it can also be defined as the the load that need to be move a body for certain distance in a certain amount of time.

mathematically,

                      h.p = (force × distance)/ time

                            = (10 × 3)/ 10

                            = 30/10

                            = 3 foot -pound/sec

hence, the horse power is needed to move the box is 3 foot-pound/second

important note: 1 h.p = 550 foot-pound/second = 746 watts