Chapter : 3. Work and Energy
Kinetic Energy
Kinetic Energy : The energy of a body due to its motion is called kinetic energy. In other words. The ability of a body to do work by virtue of its motion is called its kinetic energy.
Expression for Kinetic Energy : The kinetic energy of a body is measured in terms of the amount of work done by an opposing force that brings the body to rest from its present state of motion.
Suppose a body of mass m is moving with a velocity v and is brought to rest by an opposing force F.
Now retarding force is given by
F = ma...(1)
Now using the equation of motion,
v2 – u2 = 2as, we get
02 = v2 – 2as
∴ s =
...(2)
Kinetic energy of the body = work done by the retarding force
Kinetic energy = force × displacement = F . s...(3)
Substituting the value of F from equation (1) and the value of s from equation (2) in equation (3), we get
K.E. = ma × = 
mv2
Thus, a body of mass m and moving with a velocity v has the capacity of doing work equal tomv2 before it stops.
Expression for Kinetic Energy : The kinetic energy of a body is measured in terms of the amount of work done by an opposing force that brings the body to rest from its present state of motion.
Suppose a body of mass m is moving with a velocity v and is brought to rest by an opposing force F.
Now retarding force is given by
F = ma...(1)
Now using the equation of motion,
v2 – u2 = 2as, we get
02 = v2 – 2as
∴ s =
...(2)Kinetic energy of the body = work done by the retarding force
Kinetic energy = force × displacement = F . s...(3)
Substituting the value of F from equation (1) and the value of s from equation (2) in equation (3), we get
K.E. = ma ×
= mv2Thus, a body of mass m and moving with a velocity v has the capacity of doing work equal to
mv2 before it stops.Trending Articles & Blogs
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