Two concentric spheres of diameter 0.8 m and 1.2 m are separated by an air space and have surface temperatures of 400 k and 300 k. (a) if the surfaces are black, what is the net rate of radiation exchange between the spheres, in w?

newton's first law of motion

come closer and become far apart and become steam/gas

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

i think the answer is a and b

i wish you luck