Mechanics Homework

A train starts from rest at a station A and moves along a straight horizontal track. For the first 10 s, the train moves with constant acceleration 1.2 m s–2. For the next 24 s it moves with constant acceleration 0.75 m s–2. It then moves with constant speed for T seconds. Finally it slows down with constant deceleration 3 m s–2 until it comes to rest at a station B.

(a) Show that, 34 s after leaving A, the speed of the train is 30 m s–1.
(3)

(b) Sketch a speed-time graph to illustrate the motion of the train as it moves from A to B.
(3)

(c) Find the distance moved by the train during the first 34 s of its journey from A.
(4)
The distance from A to B is 3 km.

(d) Find the value of T.
(4)

i did all the other Questions, can i have some help with D please.

Reply 1

Bobjim12

You know that from A to B is 3km, and you know for the first 10 and 24 seconds it has traveled a certain distance (work it out using Suvats).

So you have the total distance and the distance before it begins moving constantly......then what...