What is the force that opposes motion and can be found anytime two surfaces are in contact?

friction

momentum

net force

spring forces

Kind the kinetic energy of a ball moving at 45 m/s with a mass of 0.18kg

Which family or group describe the elements in column 2? Group of answer choices nonmetals alkali metals transition metals alkaline earth metals

a skydiver jumps out of a plane. describe how gravitational potential energy changes as the skydiver falls. describe how the skydivers kinetic energy changes when the parachute opens

Zain is standing on a bridge. He tosses a ball upwards, which rises, stops, and then falls all the way to the water (30 meters below Zain). Suppose that the speed at which Zain tosses the ball 1.50 m/s, and then answer the following two questions.

Supertasters" is a term used to refer to people who are born with more taste buds than the average person.

A geologist estimates that a large boulder weighs 7840 N. What should he estimate the mass of this boulder to be? A. 650 kg B. 740 kg C. 780 kg D. 800 kg

Two objects have the same momentum. Do the velocities of these objects necessarily have (a) the same directions and (b) the same magnitudes? Give your reasoning in each case.

If you keep voltage constant and increase resistance resistance, what happens to current?

A scene in a movie has a stuntman falling through a floor onto a bed in the room below. The plan is to have the actor fall on his back, but a researcher has been hired to investigate the safety of this stunt.

During energy transformation, all energy systems: are a. 100 percent efficient b. lose energy c. gain heat energy d. create energy