Question

calculate the work done moving body of mass 20kg from rest through distance of 2meter with acceleration of 5meter per second
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Answer 1

Step-by-step explanation:

Mass of an object, m=20kg

Initial velocity of the block, v1=5ms^−1

Final velocity, v2=2ms^−1

From work-energy theorem, work done by a constant force is equal to change in its kinetic energy I.e.

W=Kf−Ki=12mv^2 2−12mv^2 1

W=1/2 m (v^2 2−v^2 1)

W=12×20×(2^2−5^2)

W=10×(4−25)=10×(−21)

W=−210J

The negative sign indicates that the force is acting in the direction opposite to the motion of an object.