Asked by kate
The driver of a 1.00X103 kg car traveling on the interstate at 35.0 m/s slams on his brakes to avoid hitting a second vehicle in front of him, which had come to rest because of congestion ahead. After the brakes are applied, a constant friction force of 8.00X103 N acts on the car. Ignore air resistance.
(a) At what minimum distance should the brakes be applied to avoid a collision with the other vehicle?
(b) If the distance between the vehicles is initially only 30.0 m, at what speed would the collision occur?
(a) At what minimum distance should the brakes be applied to avoid a collision with the other vehicle?
(b) If the distance between the vehicles is initially only 30.0 m, at what speed would the collision occur?
Answers
Answered by
scott
the car has kinetic energy ... 1/2 m v^2
to stop the car; the work done by the brakes (f * d) must equal the car's kinetic energy
(a) 1/2 * 1.00E3 * 35.0^2 = 8.00E3 * d
(b) find the work done in 30.0 m and subtract it from the initial K.E.
... the remaining energy will give the collision speed
to stop the car; the work done by the brakes (f * d) must equal the car's kinetic energy
(a) 1/2 * 1.00E3 * 35.0^2 = 8.00E3 * d
(b) find the work done in 30.0 m and subtract it from the initial K.E.
... the remaining energy will give the collision speed