Question
A body of mass 2 kg initially at rest moves under the action of an applied horizontal forces of 7N on a table with co-efficient of kinetic friction 0.1. Compute:
(a) the work done by the applied force in 10 sec.,
(b) the work done by the friction force in 10 sec.,
(c) the work done by the net force on the body in 10 sec.,
(d) the change in kinetic energy of the body in 10 sec and interpret your results.
Solution
It is given that,
Mass of the body, m = 2 kg
Force acting on the body, F = 7N
Coefficient of friction,
Time taken, t = 10 sec
The force of friction between block and surface is,
The net accelerating force on body is,
F - f = 7 - 2 = 5N
Therefore,
Mass of the body, m = 2 kg
Force acting on the body, F = 7N
Coefficient of friction,
Time taken, t = 10 sec
The force of friction between block and surface is,
The net accelerating force on body is,
F - f = 7 - 2 = 5N
Therefore,
Acceleration, 
Now the displacement undergone by the body in 10 sec is,
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(a) Work done by applied force in 10 sec.,
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(b) Work done by friction force is,
(c) Work done by net force is,
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(d) Change in kinetic energy of body is equal to the work done by net force = 625 J.
Now the displacement undergone by the body in 10 sec is,
(a) Work done by applied force in 10 sec.,
(b) Work done by friction force is,
(c) Work done by net force is,
(d) Change in kinetic energy of body is equal to the work done by net force = 625 J.
