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प्रश्न
An object of mass, m is moving with a constant velocity, v. How much work should be done on the object in order to bring the object to rest?
उत्तर
Mass of the object = m
The initial velocity of the object = v,
The final velocity of the object = 0
Work done on the object = Change in kinetic energy of the object = Final kinetic energy − Initial kinetic energy
= `1/2 M xx (0) - 1/2 m . v^2`
= `(0) - 1/2 m . v^2`
= `-1/2 m . v^2`
The negative sign shows that the work done is opposite to the object's direction of motion.
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