A 1000kg car accelerates from 0 to 20 m/s in 15 seconds. Calculate the acceleration of the car, the force required for this acceleration and the momentum of the car at 20 m/s.
The first part of the question, calculating the acceleration, uses the fact that acceleration equals the change in velocity divided by the time. In this case, the change in velocity is 20-0 and the time is 15 seconds, so 20/15 is 1.4. The units of acceleration are meters per second squared. To calculate the force we recall Newton's Second Law, F=ma, or force equals mass multiplied by acceleration. In this case F = 1000x1.4 or 1400. The units of force are Newtons (N). Finally, the momentum of the car at 20 m/s can be found using momentum equals mass multiplied by velocity. Here, we have 1000x20 = 20000 and the units are kilogram metres per second.
RM
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