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08/01/2021 4:17 pm
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Certain force acting on a 20 kg mass changes its velocity from 5 ms-1 to 2 ms-1. Calculate the work done by the force.
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08/01/2021 4:26 pm
Mass of the object, m = 20 kg Total work done by the force = Change in the kinetic energy of the object
= \(\frac{1}{2}\times m \times \Delta(v)^2\) = \(\frac{1}{2}\times m \times (v{^2_f} - v{_i^2})\)
= \(\frac{1}{2}\times 20 kg \times [(2 ms^{-1})^2 - (5 ms^{-1})^2]\)
= 10 kg x \((-21 m^2s^{-2})\)
= \(-210 kg\;m^2s^{-2}\) = -210 J
The force will do work equivalent to 210 J. Here the direction of force is opposite to the direction of motion.