Train Braking Distance Calculation

[CathyLou]

Hi.

I would really appreciate it if someone could please help me with the following M1 level kinematics question as I am really stuck.

The brakes of a train can produce a retardation of 1.7 m/s^2. If the train is traveling at 100 km/h and applies its brakes what distance does it travel before stopping?

I got that:

a = -1.7
u = 22.8 (when converted to m/s)
s = ?

but I do not know where to go from here.

Thank you.

Cathy

 

[learningphysics]

Have you studied the different equations for displacement with constant acceleration?

 

[CathyLou]

Have you studied the different equations for displacement with constant acceleration?

Just realized that v = 0!

I have got the answer now!

Cathy

 

[CathyLou]

Hi.

Could someone please help me with the following question? I have no idea how to even start it.

A particle is moving along a straight line. It passes points A, B and C on the line t = 0, t = 3 s and t = 6 s respectively. If AC is 60 m and the velocity of the particle at A is 4 m/s find the acceleration of the particle (assumed uniform) and the distance AB.

Thank you.

Cathy

 

[Saladsamurai]

Break this problem into parts. You know that from A to C 60m; $$v_0=4m/s$$ and $$t=6s$$
so you have t, v, and displacement. Do you know of any relationship between those variables?

Casey

 

[CathyLou]

Thank you so much for your help. I have figured out the answers now.

Cathy

 

[Saladsamurai]

Nice.