Q4.
What is Kinetic Energy? Derive an expression for Kinetic Energy?
Answers
Answer:
"Energy posses by a body by virtue of its motion is referred to as 'Kinetic Energy'".
Explanation:
Expression for K.E - KINETIC ENERGY-K.E = 1/2 mv2. Kinetic energy depends upon the mass and velocity of body. If velocity is zero then K.E. of body will also be zero.
Answer:
Expression for K.E - KINETIC ENERGY-K.E = 1/2 mv2. "Energy posses by a body by virtue of its motion is referred to as 'Kinetic Energy'". Kinetic energy depends upon the mass and velocity of body. If velocity is zero then K.E. of body will also be zero.Kinetic energy is a scalar quantity like other forms of energies.
Consider a body of mass "m" starts moving from rest. After a time interval "t" its velocity becomes V.
If initial velocity of the body is Vi = 0 ,final velocity Vf = V and the displacement of body is "d". Then
Using equation of motion
2aS = Vf2 – Vi2
Putting the above mentioned values
2ad = V2 – 0
a = V2/2d
Now force is given by
F = ma
Putting the value of acceleration
F = m(V2/2d)
As we know that
Work done = Fd
Putting the value of F
Work done = (mv2/2d)(d)
Work done = mV2/2
OR
Work done = ½ mV2
Since the work done is motion is called "Kinetic Energy"
i.e.
K.E. = Work done
OR
K.E. =1/2mV2.