Question

A railway train travelling along a straight track takes 1.5 minutes to come to rest from a speed of 115 km h-1. What is its average braking acceleration?

(Give your answer to 2 d.p.)

Answer 1

Answer:

Correct option is 3.125 ms −2

Answer 2

Answer:

3.125 ms-2

Explanation:

Relative velocity of faster train w.r.t. slower train u=115−25=90 km h

−1

u=90×

18

5

ms

−1

=25 ms

−1

Using v

2

−u

2

=2aS

0

2

−25

2

=2×a×100

or 200a=−625⇒a=−

200

625

ms

−2

or a=−3.125 ms

−2

.