A 20-kilogram object strikes the ground with 1960 J of kinetic energy after falling freely from rest. How far above the ground was the object when it was released? *

h = 10 m

Explanation:

Given that,

Mass of an object, m = 20 kg

It strikes the ground with 1960 J of kinetic energy after falling freely from rest.

We need to find how far above the ground was the object when it was released. Let it is h.

The kinetic energy is converted to potential energy. It can be given by the relation as follows :

So, it was at a height of 10 m when it was released.

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