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08/01/2021 5:09 pm
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Calculate the work required to be done to stop a car of 1500 kg moving at a velocity of 60 km h-1?
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08/01/2021 5:16 pm
Here, mass of the car, m = 1500 kg Initial velocity of the car, u = 60 km h-1
= \(\frac{60 \times 1000m}{60 \times 60s}\) = \(\frac{50}{3}ms^{-1}\)
Initial kinetic energy of the car,
\(K.E_i = \frac{1}{2}mu^2\)
= \(\frac{1}{2}(1500 \;kg)(\frac{50}{3}ms^{-1})^2\) = 208333.3 J
Final kinetic energy of the car,
\(K.E_f = \frac{1}{2}mv^2 = 0\)
Change in kinetic energy of the car
= \(K.E_f - K.E_i\) = -208333.3 J
The minus sign indicates that the work is being done against the moving car.