Question

An object of mass
40 kg is raised to a height
of 5m above the ground. What is the potential
energy? If the object is allowed to fall, find its
Kinetic energy when it is half-way down.​

Answer 1

Explanation:

At a height of 5 metre object has a potential energy of 2000 J. When this object is allowed to fall and it is Half way down its height above the ground will be half of 5 m= 5/2= 2.5m. Potential Energy at Half way down= 1000 joules.

Answer 2

Given

Mass of the object = 40kg

Height = 5m

Find out

We need to find Potential energy and also its kinetic energy when it is half-way down

Solution

Potential energy (U) is given by the expression,

U= mgh

Where,

m = Mass of the object

h = Vertical displacement

g = Acceleration because of gravity = 9.8 ms-2

W= 40 X 9.8 X 5

W= 1960 J

At half-way down, the Kinetic energy of the item are going to be

At this time, the item has an equal quantity of potential and K.E.

This can be due to law of conservation of energy. Hence, half-way down, the K.E. of the object can be calculated as

1960 J/ 2 = 980 J

half way down = 980 J