A train moves from rest to a speed of 25 m/s in 30.0 seconds. What is the acceleration?

Explanation:

Uniform Acceleration

When an object changes its velocity at the same rate, the acceleration is constant.

The relation between the initial and final speeds is:

Where:

vf  = Final speed

vo = Initial speed

a   = Constant acceleration

t   = Elapsed time

It's known a train moves from rest (vo=0) to a speed of vf=25 m/s in t=30 seconds. It's required to calculate the acceleration.

Solving for a:

Substituting:

prolly a beacuse the momentuem the car has increases while going down hill