Can someone help me to solving this problem pleasee!!

* Two blocks are connected by a light weight, flexible cord that passes over a frictionless pulley. If m1 = 3.6kg and m2 = 9.2kg, and block 2 is initially at rest 140cm above the floor, how long does it take block 2 to reach the floor?

And another question is:

*A train is traveling south at 24.0m/s when the brakes are applied. It slows down with a constant acceleration to a speed of 6.00m/s in a time of 9.00s. (a) Draw a graph of Vx versus t for a 12-s interval (starting 2 s before the brakes are applied and ending 1 s after the brakes are released). Let the x-axis point to the north. (b) What's the acceleration of the train during the 9.00-s interval? (c) How far does the train travel during the 9.00 s?

problem one: m2 is connected to m1. m2 is heavier so it'll fall, pulling m1 up. m1 pulls on m2 through the string in the opposite direction, so the effective mass of m2 isn't 9.2kg, since m1 pulls in the opposite direction with mass 3.kg (the pull is actually gravity acting on m1 in a downward direction, but again... m1 connects to m2 through a rope that goes up, over a pulley, and down to m2). So... what is the effective mass of m2. You could also figure this out using forces instead of mass, but its just as easy here to figure out the effective mass of m2.

then you use the effective mass and the acceleration due to gravity to determine time. You'll need to use formulas that use time, acceleration, distance.

second problem. You need to figure out the constant decceleration of the train. If I said you went from 100 to 0mph over 10s with constant decceleration that would mean I slowed from a velocity of 100mph/10s = 10mph/s... every second I slowed by 10 mph. 100 at time brake applied, 90 at 1s, 80 at 2s... etc.

so figure out the decceleration using your numbers and apply them like the ex I gave