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Certain force acting on a 20 kg mass changes its velocity from... - Science
Question
Certain force acting on a 20 kg mass changes its velocity from 5 m s⁻¹ to 2 m s⁻¹. Calculate the work done by the force.
Answer
Given:
Mass (m) = 20\text{ kg}
Initial velocity (u) = 5\text{ m s}^{-1}
Final velocity (v) = 2\text{ m s}^{-1}
Formula:
Work Done = Change in Kinetic Energy
W = \frac{1}{2} m (v^2 - u^2)
Calculation:
W = \frac{1}{2} \times 20 \times (2^2 - 5^2)W = 10 \times (4 - 25)W = 10 \times (-21)W = -210\text{ J}
Answer:
The work done by the force is -210\text{ J}.
(The negative sign indicates that the force is acting opposite to the direction of motion).
