Question

A train accelerates at a rate of 2.5 km/hr/sec. During the acceleration period, its velocity changes by 55 km/hr. Choose the exact time of the train's acceleration.

A. 1,200 s

B. 22 hr

C. 22 s

D. 0.045 s

Answer 1

Using the formula :
v = u + at
a = accelaration = 2.5 km/hour^2
v = final velocity = 55 km / hour
u = initial velocity (in this case u=0)
t = time

hence,
v = 0 + at
v = at
55 km /hour = 2.5 km/hour^2 * t
t = 55 km /hour / 2.5 km/hour^2 
t = 22 hours