A cup contains 500 g water initially at a temperature of 100oC. This cup is put in a large room of temperature of 20oC.
a/ What will be the temperature of the water if the cup stays in the room for a long time? Explain your
answer.
b/ Compute the change of entropy of the system water – room, knowing that the heat capacity of water is
4186 J/(kg. K).

the minimum constant speed at which she can catch the train is 2.7 m/s

given:

acceleration = 0.6

time = 4.5 s

to find:

velocity = ?

formula used:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

solution:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

v = 0 + (0.6 × 4.5)

v = 2.7 m/s

the minimum constant speed at which she can catch the train is 2.7 m/s