A car of 900kg accelerates uniformly from rest to a speed of 30 m/s in 15 seconds.what is its power?
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To determine the power of the car, we need to use the formula for power, which is:
Power = Work / Time
In this case, the work done by the car is equal to the change in its kinetic energy. The formula for kinetic energy is:
Kinetic Energy = (1/2) * mass * velocity^2
Since the car starts from rest, its initial velocity is 0. Therefore, the change in kinetic energy is:
Change in Kinetic Energy = (1/2) * mass * final velocity^2
Now, let's calculate the change in kinetic energy:
Change in Kinetic Energy = (1/2) * 900 kg * (30 m/s)^2
= 405,000 Joules
Next, we need to calculate the time it took for the car to reach its final velocity. We are given that the time taken is 15 seconds.
Now, we can substitute these values into the power formula:
Power = Change in Kinetic Energy / Time
= 405,000 Joules / 15 seconds
= 27,000 Watts
Therefore, the power of the car is 27,000 Watts.