A 1000-kg car is moving at 30 km/h. It accelerates uniformly to 70 km/h over 15 seconds. The average rolling resistance is 500 N. What is the average tension in the tow cable pulling the car?
Explanation
This problem uses Newton's second law (ΣF=ma) in an average sense. First, the constant acceleration is determined from the change in velocity over time. Then, the average tension is found by summing the forces (tension minus resistance) and equating them to the product of mass and acceleration.
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