Which describes free fall? A. When an object is thrown downward against gravity.

B. When gravity and air resistance act on a falling object.

C. When no gravity acts on a falling object.

D. When only gravity acts on a falling object.

The percent efficiency of a machine can never be 100% (or greater), because in the real world some energy is always converted into a. heat b. work c. input force d. output force

In positive numbers less than 1, the zeros between the decimal point and non zero are significant

Agas initially at p1 = 1 bar and occupying a volume of 0.5 liter is compressed within a piston–cylinder assembly to a final pressure p2 = 4 bar. (a) if the relationship between pressure and volume during the compression is pv = constant, determine the volume, in liters, at a pressure of 3 bar. (b) repeat for a linear pressure–volume relationship between the same end states. reference