You are holding a bottle of pop in your hands on a bus. The bubbles in the pop are going straight up. Suddenly, the bus brakes hard to avoid a road hazard. How is the motion of the bubbles in the pop affected?
a) The bubbles will gain some motion towards the front of the bus.
b) The answer depends on the initial speed of the bus.
c) The motion of the bubbles will not change.
d) The bubbles will gain some motion towards the back of the bus.