A runaway train car that has a mass of 15,000 kg travels at a speed of 5.4 m/s down a track. Compute the time required for a force of 1500 N to bring it to rest. (a) 0.019 s
(b) 54s
(c) 4.2Ã106s
(d) 2.4Ã10â7s

54 s

Explanation:

Given that,

Mass of a car, m = 15000 kg

Initial speed, u = 5.4 m/s

Final speed, v = 0 (it comes to rest)

Force, F = 1500 N

We need to find time when it comes to rest. Let it is t. Net force is given by :

F = ma, a is acceleration of the car

So, it will take 54 seconds to come to rest.

inverse v=i*r

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