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.

The electric potential a distance r from a small charge is proportional to what power of the distance from the charge? a. r^-1 b. r c. r^-2 d. r^2

Astone is dropped from the upper observation deck of a tower, 250 m above the ground. (assume g = 9.8 m/s2.) (a) find the distance (in meters) of the stone above ground level at time t. h(t) = (b) how long does it take the stone to reach the ground? (round your answer to two decimal places.) s (c) with what velocity does it strike the ground? (round your answer to one decimal place.) m/s (d) if the stone is thrown downward with a speed of 2 m/s, how long does it take to reach the ground? (round your answer to two decimal places.) s

Does current flow through or across a resistor?