Question

Amy gets up from her seat on a train to move closer to the front. Just as she begins to walk forward, the train stops at a station. What is the best explanation of what happens to Amy?
A. While Amy is walking, her body is in motion. When the train stops, because she's not buckled in, Amy continues to move forward due to inertia.

B.  While Amy is walking, her body is in motion. When the train stops, an unbalanced force accelerates her body backward. 

C. While Amy is walking, her body is in motion, but as the train stops, it exerts a force on Amy opposite to the direction she is walking, causing her to stop as well. 

D. While Amy is walking, she is in motion due to the force of repulsion. When the train stops, she is catapulted forward due to the train's stronger force of attraction. 

My best guesses would be D or C, but only from what common sense tells me. Answer and explanation, please? Thanks guys!

Answer 1

Have you ever been in a bus, a train, or a car ?
What happens to you when it stops suddenly ?

A body in motion continues in motion unless
an external force acts on it and makes it stop.

Amy's body keeps moving forward when the train stops.
She pitches forward, and if she doesn't reach out and grab
a seat or a seated person, she may lose her footing and fall
on her face.

Choice - 'A' is a very good explanation.
The other choices aren't.

'C' is a good hunch, but it only applies to her feet.
The rest of her keeps going.

'D' is nonsense.  There are no mysterious forces of
'repulsion' or 'attraction' on the train.

Answer 2

The answer to your question is A. While Amy is walking her body is in motion. When the train stops, because she's not buckled in, Amy continues to move forward due to inertia.