NEET-XII-Physics
08: Work and Energy
- #16A ball is given a speed v on a rough horizontal surface. The ball travels through a distance l on the surface and stops. (a) what are the initial and final kinetic energies of the ball? (b) What is the work done by the kinetic friction?Ans : (a) Initial kinetic energy of the ball, `` {K}_{i}=\frac{1}{2}m{v}^{2}``
Here, m is the mass of the ball.
The final kinetic of the ball is zero. (b) Work done by the kinetic friction is equal to the change in kinetic energy of the ball.
∴ Work done by the kinetic friction = `` {K}_{f}-{K}_{i}=0-\frac{1}{2}m{v}^{2}``
= `` -\frac{1}{2}m{v}^{2}``
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- #16-awhat are the initial and final kinetic energies of the ball?Ans : Initial kinetic energy of the ball, `` {K}_{i}=\frac{1}{2}m{v}^{2}``
Here, m is the mass of the ball.
The final kinetic of the ball is zero.
- #16-bWhat is the work done by the kinetic friction?Ans : Work done by the kinetic friction is equal to the change in kinetic energy of the ball.
∴ Work done by the kinetic friction = `` {K}_{f}-{K}_{i}=0-\frac{1}{2}m{v}^{2}``
= `` -\frac{1}{2}m{v}^{2}``
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