a 1200-kg automobile travels at a speed of 90-km/h (a)what is the kinetic energy? (b) what is the net work that would be required to bring it to a stop?
2 answers
(a) Convert 90 km/h to m/s, and calculate (1/2) M V^2. (The answer to b) is the same as (a).
The stopping distance of a vehicle is an important safety factor. Assuming a constant braking force, use the work-energy theorem to show that a vehicle's stopping distance is proportional to the square of its initial speed. If an automobile traveling at 45 km/h is brought to a stop in 50 m, what would be the stopping distance for an initial speed of 90 km/h?
4 answers