21% of the atmosphere a:Nitrogen B:Oxygen C:CO^2 D:Argon

A 5-kilogram rock is perched on a cliff 6 meters above a lake. How much gravitational potential energy does the rock have? OA) 30 J O B) 90 J OC) 147 OD) 294

Mike walked 450 m west. he then turned and walked 150 m to the east in 300 seconds. what is his velocity?

What happens to the temperature of the water inside the beaker after all of the ice melts? Why?

To determine the number of neutrons in an atom, what must be done? A. Add the atomic mass to the atomic number. B. Add the atomic number to the number of protons. C. Subtract the atomic number from the atomic mass. D.

Melting, boiling, anf bending are physical changes but why is burning a chemical change

A set of data is collected from a simple circuit with a 20 resistor and is represented in the table

A skydiver of mass m jumps from a hot air balloon and falls a distance d before reaching a terminal velocity of magnitude v. Assume that the magnitude of the acceleration due to gravity is g. a.

8. What happens to force when mass is increased?

Give an example of ionic and covalent bond, and explain and make an example for each.

Which of these is the best reason for proper nutrition? A. To ensure that you will be skinny B. To protect yourself against certain diseases C. To improve your intelligence D. To ensure that you will get good grades