Hot air at 80°c is blown over a 2-m x 4-m flat surface at 45°c. if the average convection heat transfer coefficient is 55 w/m2·k, determine the rate of heat transfer from the air to the plate, in kw.

Answer : The rate of heat transfer from air to plate is 22 KW

Explanation :

It is given that,

Temperature of flat surface,

Temperature of flat surface,

Area of surface,

Heat coefficient,

So, rate of heat transfer,

Hence, the rate of heat transfer from air to plate is 22 KW

i think the answer would be reserve.

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