A. [2]
A train covers 450 km in 5 hr. between Station A and Station B.
What is the average speed of train in km/h and m/s.

90 km/h

50 m/s

Explanation:

Distance = 450 km

Time = 5hrs

Speed = Distance/Time

450/5 = 90 km/h

1 km = 1,000 m

1 hr = 60m = 60 x 60 = 3,600 sec

but since it's 5hrs = 60 x 300m = 18,000

90 x 1,000 = 90,000/18,000 = 50 m/s

we need answer choices

the minimum constant speed at which she can catch the train is 2.7 m/s

given:

acceleration = 0.6

time = 4.5 s

to find:

velocity = ?

formula used:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

solution:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

v = 0 + (0.6 × 4.5)

v = 2.7 m/s

the minimum constant speed at which she can catch the train is 2.7 m/s