The cup is acted upon by an unbalanced force which is the cars acceleration, but before it was an object at rest that stayed at rest. This jet propels their body forward.
This can be seen through the fact that Aksionov has the ability to seek his own justice many times throughout the story, yet does not take it
The intensity of the light has no connection with the photoelectric effect.
That's what was so baffling about it before the particle nature of light
was suspected ... a match with a blue flame might stimulate the
photoelectric effect, but a high-power red searchlight couldn't do it.
Acceleration = change in velocity / time
change in velocity = final velocity - initial velocity
because the object is slowing down, the acceleration will be negative.
acceleration = (4-34) / 60
acceleration = -30 / 60
acceleration = -0.5 m/s^2
answer : the train is accelerating at -0.5 m/s^2
