Which of the following is an example of heat transfer through radiation?
a. a pot of soup warming on a hot burner.
b. a crayon melting on a hot sidewalk.
c. beach sand getting warmed by the sun.
d. an egg getting cooked in a pot of boiling water.

A). The hot burner is in contact wit the pot,
warming it with conduction.

B).  The hot sidewalk is in contact with the crayon,
melting it with conduction.

C).  The sun is not in contact with anything, and there is
no fluid to convect between it and the sand.  The only way
for the sun to transfer heat to the sand is with radiation.

D).  The boiling water is in contact with the egg,
warming it with conduction.

Is a  vector quantity  that refers to "the rate at which an object changes its position." imagine a person moving rapidly - one step forward and one step back - always returning to the original starting position. while this might result in a frenzy of activity, it would result in a zero velocity. because the person always returns to the original position, the motion would never result in a change in position. since velocity is defined as the rate at which the position changes, this motion results in zero velocity. if a person in motion wishes to maximize their velocity, then that person must make every effort to maximize the amount that they are displaced from their original position. every step must go into moving that person further from where he or she started. for certain, the person should never change directions and begin to return to the starting position.

Ithink the answer is d i hope it my friend message me if i’m wrong and i’ll change my answer and fix it for you