A subway train starting from rest leaves a station with a constant acceleration. At the end of 7.55 s, it is moving at 17.818 m/s. What is the train’s displacement in the first 4.5753 s of motion?

A subway train starting from rest leaves a station with a constant acceleration. At the end of 7.55 s, it is moving at 17.818 m/s. What is the train’s displacement in the first 4.5753 s of motion? Answer in units of m
Exactly 2.7 after a projectile is fired into the air from the ground, it is observed to have a velocity = (8.2 + 4.7 ), where the axis is horizontal and the axis is positive upward What is the horizontal range of projectile.
the gravitational force between two objects that are 2.1×10^-1 m apart is 3.2×10^-6 N. if the mass of one object is 55 kg what is the mass of the other object?