Question

A runaway train car that has a mass of 15,000 kg travels at a speed of 5.4 m/s down a track. A force of 1500 N brings the car to rest. How far (in meters) does the train travel while stopping?

Answer 1

Answer:

145.8 m

Explanation:

M = mass of the runaway train car = 15,000 kg

V₀ = initial speed of the train = 5.4 m/s

V = final speed of the train = 0 m/s

F = force applied to bring the car to rest = 1500 N

d = distance traveled before stopping

Using work-change in kinetic energy theorem

Work done by applied force = Change in kinetic energy

- F d = (0.5) M (V² - V₀²)

- (1500) d = (0.5) (15000) (0² - 5.4²)

d = 145.8 m