Question

For typical rubber-on-concrete friction, what is the shortest time in which a car could accelerate from 0 to 50 mph? Suppose that μs=1.00, μk=0.80, and μr=0.02.

It's possible for a determined group of people to pull an aircraft. Drag is negligible at low speeds, and the only force impeding motion is the rolling friction of the rubber tires on the concrete runway. In 2000, a team of 60 British police officers set a world record by pulling a Boeing 747, with a mass of 200,000 kg, a distance of 100 m in 53 s. The plane started at rest.Suppose that ?r=0.02.Estimate the force with which each officer pulled on the plane, assuming constant pulling force and constant acceleration.

Answer 1

The final speed of the car is, (1609.34 m 1h v 50 mplh 1 mile 3600 s - 22.35 m/s Apply Newton's second law to the car From Newton's second law, the minimum net force required to move the car is equal to the force due to friction. So, m/s -9.8 m/s The acceleration can also be expressed as follows (22.35 m/s)-(0) 9.8 m/s 2.28 s