How can pieces of rock in contact with a stream bed move?

When a box rests on a round sheet of wood on the ground, it exerts an average pressure p on the wood. If the wood is replaced by a sheet that has half the diameter of the original piece, what is the new average pressure?

A skateboarder is accelerating forward.

At what age is the human brain fully developed?

What would spica's parallax be if it were measured from an observatory on neptune's moon triton as neptune orbited the sun?

There is a form of light that is very energetic and can cause damage to living cells and tissues. The Sun emits this type of light, but much of it is blocked by ozone in the atmosphere.

An object's weight is equal to its buoyant force in water. What would you expect to happen when the object is placed in water? Explain your reasoning.

What is the name of the german scientist that proposed the theory of continental drift

Trucks 1 and 2 are traveling at the same constant velocity but truck 1's energy due to motion is two times less than that of truck 2. This is because Truck 1's mass is:

Why do the densities of most substances decrease with an increase in temperature?

Consider two planets in space that gravitationally attract each other if the mass of one of them stays the same and the mass of the other is doubled AND the distance between them is doubled, then the force between them changes by what factor? A.