Susan is standing in an empty Metro (subway) car which is travelling at constant velocity. Suddenly, because of an emergency, the driver applies the brakes. Select True or False for each of the following statements.
a) If she immediately grabs onto the seat behind her (she is facing forwards), then she must push on the seat to avoid falling.
b) If she immediately jumps straight up into the air, she will land closer to the front of the car.
c) She falls forwards -- i.e. towards the front of the car.
d) She falls because there is no force acting on her which can be large enough to slow her down.
The Attempt at a Solution
I'm stuck on this exercise. I think that statement a), b) and c) should be true because as when the train breaks, the train moves while the girl isn't, and this would imply that the girl gets thrown forward. However, I'm not sure on the wording of statement d). I'm also in doubt with statement a), as if she pushed on the seat she would simply go forward.