Work, Energy and Power


   
 
Momentum
We know that all moving objects possess momentum. Momentum of the body is defined as the product of its mass and the velocity.
 
Now let us see how kinetic energy of a body is related to its momentum.
 
Consider a body of mass 'm' moving with a velocity 'v'. Then, momentum of the body, p = mv
 
 
 
Substituting the value of v in eqn (1) we get,
 
 
 
 
Numericals
 
01. Calculate the kinetic energy of a body of mass 5 kg, which is moving with a velocity of 15m/s.
 
Solution:
 
Mass of the body (m) = 5kg
 
Velocity of the body (v) = 15m/s
 
Kinetic energy = 1/2mv2
 
 
 
 
Kinetic energy = 562.5 J
 
02. A dog of mass 20kg is running at a constant speed of 12m/s. Calculate the kinetic energy of the dog while it is running.
 
Solution:
 
Mass of the dog (m)=20kg
 
Velocity (v)=12 m/s
 
 
 
 
 
 
     
   
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