Question

On a particular railway a train driver applies the brake of the train at a yellow signal a distance of 1.0 kilometre from a red signal where the train stops the maximum deceleration of the train is 1.1 metres per second square assuming uniform deceleration what is the maximum safe speed of the train at the yellow signal
a.2.2m/s b.20m/s c.47m/s d.220m/s​

Answer 1

Answer:

For Nov 2009 Paper 11 Q5 – Answer: A.

For Nov 2013 Paper 13 Q8 – Answer: B.

Consider the equation for uniformly accelerated motion: v2 = u2 + 2as

Final velocity, v = 0

Acceleration, a = -0.2ms-2

Distance, s = 1000

Initial velocity, u = ???

So, 0 = u2 + 2(-0.2)(1000) giving u = 20ms-1