Francine is dragging a heavy toolbox across a rough, cement floor. What is a contact force that is acting on the box as Francine pulls it.

A.

static electricity

B.

gravity

C.

magnetism

D.

friction

6–48 bananas are to be cooled from 24 to 138c at a rate of 215 kg/h by a refrigeration system. the power input to the refrigerator is 1.4 kw. determine the rate of cooling, in kj/ min, and the cop of the refrigerator. the specific heat of banana above freezing is 3.35 kj/kg·8c.

Suppose that 27 j of work is needed to stretch a spring from its natural length of 6 m to a length of 9 m. (a) how much work is needed to stretch the spring from 12 m to 14 m? j (b) how far beyond its natural length will a force of 78 n keep the spring stretched?

What is the measure of how much matter is in an object and that can be measured using a balance? a. height b. volume c. weight d. mass