Question

An express subway train passes through an underground station. It enters at t=0 with an initial velocity of 24.0 m/s and decelerates at a rate of 0.150 m/s^2 as it oes through. The station is 200m long.

a.) How long is the nose of the train of the station?

b.) How fast is it going when the nose leaves the station?

c.) If the train is 130 m long at what time t does the end of the train leave the station?

d.) What is the velocity of the end of the train as it leaves?

Answer 1

a) part is not clear as to what it is asking. do comment and i'll surely help u

b) using,

v² - u² = 2as

v =sqrt(u² +2as)

{a is negative since it is decelerating}

v = sqrt(24² - 2*0.15*200)

v=22.71 m/s

c) total distance to be travelled, s= 200+130 = 330 m

using,

s= ut+ 0.5*a*t²

330 = 24*t - 0.5*0.15*t²

solving the above equation and ignoring the negative answer

t=333.20 seconds

d) using,

v² - u² = 2*a*s

v =sqrt(u² +2as)

{a is negative since it is decelerating}

v = sqrt(24² - 2*0.15*330)

v=21.84 m/s