Question

Derive an expression for the kinetic energy of the body? Calculate the kinetic energy for a
body of mass 5 Kg moving a velocity 2.5 m/s2

Answer 1

Solution :

Let us consider a body which has a definite mass m.

Thus, Newtons Second law is applicable on this object ;

Suppose that it initially moves with a initial velocity u and a final velocity v.

Then,

v^2 - u^2 = 2as , according to Newtons second law of motion.

We also know that :

Work = Force x Displacement

> Work = ma x [ v^2 - u^2/2 ]

> Work  = 1/2 m ( v^2 - u^2)

But, work is nothing other than the change in kinetic energy of a body over a period of time.

In the ideal cases. the initial velocity is taken as 0.

So, kinetic energy of a moving body is 1/2 mv^2 .

Now,

Given mass : 5 kg

Given Velocity : 5/2 m/s

Kinetic Energy = 1/2 x 5 x 25/4

> 125/8

> 15.625 J

This is the required answer.

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Answer 2

Answer:

Explanation:

Let us consider a body which has a definite mass m.

Thus, Newtons Second law is applicable on this object ;

Suppose that it initially moves with a initial velocity u and a final velocity v.

Then,

v^2 - u^2 = 2as , according to Newtons second law of motion.

We also know that :

Work = Force x Displacement

> Work = ma x [ v^2 - u^2/2 ]

> Work  = 1/2 m ( v^2 - u^2)

But, work is nothing other than the change in kinetic energy of a body over a period of time.

In the ideal cases. the initial velocity is taken as 0.

So, kinetic energy of a moving body is 1/2 mv^2 .

Now,

Given mass : 5 kg

Given Velocity : 5/2 m/s

Kinetic Energy = 1/2 x 5 x 25/4

> 125/8

> 15.625 J

This is the required answer.