What is the acceleration of the train if it takes 8 seconds to reach 45 m/s?

Answer:5.6m/s^2

Explanation: Since the initial velocity (u) was not given, it's assume that the train was at rest hence it's initial velocity (u) = 0

From Newton's first equation of motion,

Where v=u+at, where v = final velocity, u = initial velocity, a = acceleration and t = time

Now given v = 45 u=0 t=8 and a=? Substituting the values into the equation, thus : 45 = 0+8a making a the subject in the relation, a = 45/8 = 5.6m/s^2. As the acceleration of the train