___ devices need constant power to operate. The timing functions are initiated by the presence or absence of a separate ""trigger"" signal.

Bone-strengthening physical activity done increases bone-mineral content and bone density in youth.

Determine the amount of work done when a crane lifts a 100-n block form 2m above the ground to 6m above the ground

"an open tank has the shape of a right circular cone. the tank is 6 feet across the top and 5 feet high. how much work is done in emptying the tank by pumping the water over the top edge? note: the density of water is 62.4 lbs per cubic foot."