Amelia's teacher called her in one day and told her that she was really proud of her because when a student fell and hurt her knee, she was the only one that wasn't laughing. However, when Amelia replied back to her teacher, she said she would've laughed if she could've. Why didn't she laugh?
Answer:
It was Amelia herself that fell and hurt her knee.
In the back. See, the train is still accelerating as it is leaving the station so the train will be moving faster when the back of the train enters the tunnel.
In the back. The train will be accelerating so it will be going faster when the back of the train enters the tunnel so a person in the back will spend less time in the tunnel.