KINETIC ENERGY
KINETIC ENERGY | ||
"Energy posses by a body by virtue of its motion is referred to as ‘Kinetic Energy’".
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FORMULA | ||
K.E. = 1/2 mv2
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Kinetic energy depends upon the mass and velocity of body. If velocity is zero than K.E. of body will also be zero. | ||
Kinetic energy is a scalar quantity like other forms of energies. | ||
DERIVE: K.E = 1/2 mv2 | ||
PROOF
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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 | ||
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First of all we will find the acceleration of body. | ||
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 accleration 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. |
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