The equation e=mc^2 relates energy and.
a. force.
b. mass.
c. gravity.
d. work.

The of a machine determines its "usefulness." a. input force b. output force c. mechanical advantage

When you turn on a battery-operated device, an electrical circuit is

If an astronaut takes an object to the moon the following is true (choose only one). a the mass will change but the weight will be the same. b both the mass and the weight of the object will be the same. c the weight will change but the mass will be the same. d both the mass and the weight of the object will change.