What element has 81 protons in the nuclei of atoms

Scientist have measured that the vibrations of an earthquake travel faster through solid rocks in the Earth and slower in the liquid magma deep in the Earth. This data supports the idea that A.

How to define acceleration

An earthquake 50km from a city produces P and S waves that travel outward at 5000 and 3000 m/s, respectively. Once city residents feel the shaking of the P wave, how much time do they have before the S wave arrives?

Using Newton's laws, describe what happens to your body when you get in a car crash. Why is important to wear a seat belt and have airbags?

If you stand next to a wall on a frictionless skateboard and push the wall with a force of 50 N, how hard does the wall push on you? Express your answer to two significant figures and include the appropriate units.

According to Newton's second law of motion acceleration or an object depends upon the ___ of the object and the ___ Acting on it. I'm confused on what the blanks are. I can't find them.

What is the concentration of H + ions at a pH = 7?

Suppose that Paul D. Trigger fires a bullet from a gun. Will the speed of the bullet leaving the muzzle will be the same as the speed of the recoiling gun? Explain.

A certain rock contains large jagged pieces of other rocks cemented by fine particles what type of rock is this explain

Could a nucleus that has one proton but no neutrons exist?