Answer:581.87 K
Explanation:
Given
Sphere is melted to form a square
Let the radius of sphere be r and square has a side a
Therefore

Surface area of sphere 
Surface area of cube 
Total emmisive remains same
Thus 







Answer:
I think it's 3 c only the loudness of the sound
Answer:
2.4 m/s
Explanation:
Given:
Velocity of the object moving north = 2.1 m/s
Velocity of the river moving eastward = 1.2 m/s
The resultant velocity is the vector sum of the velocities of object and river.
Since the directions of velocity of object and river are perpendicular to each other, the magnitude of the resultant velocity is obtained using Pythagoras Theorem.
The velocities are the legs of the right angled triangle and the resultant velocity is the hypotenuse.
The magnitude of the resultant velocity (R) is given as:

Therefore, the resultant velocity has a magnitude of 2.4 m/s.
At certain altitude, the temperature of air decrease, The air becomes saturated and water vapour molecules starts condensing.
As the altitude of air increase, the atmospheric pressure decrease due to which the temperature of the air decrease. The water molecules in the atmosphere start condensing, which saturate the air (that is air can no hold water molecules), due to which the water vapour molecules starts condensing and falls on the earth in the form of rain.