Question

VI. Numericals:
height of 4 m above the ground. (Take g = 10 m/s)
of a body of mass 400 g when it is lifted to a
[Ans. 16 J]
2. A boy kicks the football of mass 500 g which is initially at rest. It starts moving with a
constant velocity of 5 m/s . Calculate:
(a) the kinetic energy of the boy
(b) the work done by the boy
[Ans.(a) 6.25), (b) 6.25 ]
3. The mass of a body is 50 kg. It is moving with a velocity of 25 m/s. What is its kinetic
energy?
[Ans. 15625 ]​

Answer 1

Answer:

Explanation:

1. Given :-

Mass of body = 400 g

or, 0.4 kg

g = 10m/s²

Height = 4 m

Answer:-16 j

Solution:-

Gravitational potential energy:- The energy possessed by a body due to height above from the surface of earth is called gravitational potential energy.

The formula of gravitational potential energy is given by :-GPE = mgh

Now, put the given value

GPE = mgh

          4/10* 10 *4

         =4*4

        =16

hence, gravitational potential energy is 16j.

2. k.e= 1/2*m*v^2

       = 1/2* 0.5* 5^2

      = 6.25 J

work done= 6.2 J

3. k.e= 1/2*m*v^2

       = 1/2 *50* 25^2

      = 15625 J