Question

(a)What do you understand by kinetic energy of a body?
Derive an expression for it.
​

Answer 1

Answer:

The kinetic energy of an object is the energy that it possesses due to its motion. It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. It is clear that the work done is equal to the change in the kinetic energy of an object. ...

Kinetic energy of an object is the energy that it possesses due to its motion. It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity.

Derivation:  

Let us consider an object of m which is at rest lying on a table.

Let A force F acts on the object which moves the object through a distance S.

The workdone=F×S

W=F  net  ×S-------(1)

Let the work done on the object causes a change in its velocity from u to V and let a be the acceleration.

From Third equation of motion:

V²−u²=2as

s=V²−u²/2a----------(2)

By Newton's Second law:

F=ma------(3)

From equation (1), (2) and (3)

W=ma×(V  

2  −u  2  /2a)=(1/2)m(V  2  −u  2 )

As we assumed object at rest, u=0

W=(1/2)mV  2

 

we know that the kinetic energy of a body moving with a certain velocity is equal to work done on the object to acquire that velocity from rest.

∴K.E=1/2mV  2

Explanation:

Answer 2

Answer:

a energy that will produce by speed of system