Question

A train’s velocity is slowly decreasing as it approaches a station. About 1 km before it reaches the station, several stowaways jump off the train. What happens to the amount of acceleration if the force remains constant? Assume the train is traveling in the positive direction.

Answer 1

Answer:

Acceleration will exist but in -ve direction

Explanation:

As we know that the velocity is changing and decreasing , and we know that the acceleration is actually a rate of change of velocity.  in this case the train is stopping , its velocity is changing so the acceleration will exist.

now come to the 2nd point of constant force being applies to keep the body in motion.

As far as the force is concern we know that to change the state of a body force is necessary otherwise body will not change its state. in this case a constant force is applied to keep the body in motion  while on the other hand stopping forces is also being applied

Stopping force can be the frictional force. it can be the brake force applied , it can be several stop away jumps of the train  so even with the constant force train will stop , acceleration will be there but in negative direction.

Answer 2

your question is ---> A trains velocity is slowly decreasing as it approaches a station. About 1 km before it reaches the station several stowaways jump off the train. What happens to the amount of acceleration if the force remains constant? Assume the train is traveling in the positive direction.

1. It will become less negative.
2. It will become more negative.
3. It will remain the same.
4. It will become more positive

answer : option (2) it will become more negative.

explanation : it is given that,

force remains constant.

i.e., F = ma = constant.

so, a ∝ 1/m

here, about 1 km before it reaches the station, several stowaways jump off the train. means, mass (m) decreases.

so, acceleration (a) increases.

also a/c to question, A train’s velocity is slowly decreasing as it approaches a station.

it means, acceleration increases in opposite direction of its motion. so, acceleration will become more negative.