A car has 1000 kg mass and accelerates from 0 to 25m/s in 10 s. What will be the power of the car?

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justaguide | College Teacher | (Level 2) Distinguished Educator

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Power is the work done per unit time. The mass of the car is 1000 kg and work is done to increase its speed from 0 m/s to 25 m/s in 10 s.

The kinetic energy of an object with mass m and moving at v m/s is given by the expression (1/2)*m*v^2.

At rest, the kinetic energy of the car is (1/2)*1000*0^2 = 0 J. 10 seconds later it is moving at 25 m/s. The kinetic energy of the car is (1/2)*1000*25^2 = 312500 J.

In 10 s, the change in energy is 312500 J. The power required to achieve this is equal to 31250 W or 31.25 kW.