You throw a rock upward. the rock is moving upward, but it is slowing down. if we define the ground as the origin, the position of the rock is and the velocity of the rock is

a. positive, positive
b. positive, negative
c. negative, positive
d. negative, negative

A. Positive, positive

Explanation:

As we defined the ground is the origin, as long as the rock is above the ground, its position would always be positive.

As for velocity, as long as the rock is moving upwards, its direction is also upward, so its velocity is always positive. The velocity will become negative when the rock falls down.

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