Question

An train car of total mass of 13000 kg is pulling into a station and slowing down with an acceleration of -4.56 m/s^2. Before the train pulls into the station, a group of 7 stowaway jump off the train. Each stowaway has a mass of 66 kg. If the braking force on the train remains the same, what will be the acceleration of the train once the stowaways jump out of the train?

Answer 1

Answer:

-4.73 m/s²

Explanation:

Each jumper represents about 1/2 of 1% of the mass of the train, so together they total about 3.5% of the mass of the train. If the mass decreases by 3.5% and the braking force remains the same, the acceleration (magnitude) will increase by about 3.5%.

The acceleration will be about 0.17 m/s² more (in magnitude) than it was, or about -4.73 m/s².