Which of these can Waves transfer energy through?

All of the above

Liquids

Vacuums

Solids

Gasses

Friction in machines is commonly reduced by using what?

When Maggie applies the brakes of her car, the car slows uniformly from 15.3 m/s to 0 m/s in 2.23 s. How far ahead of a stop sign must she apply her brakes in order to stop at the sign? Answer in units of m

A 16.0 m long, thin, uniform metal rod slides north at a speed of 21.0 m/s. The length of the rod maintains an east-west orientation while sliding. The vertical component of the Earth's magnetic field at this location has a magnitude of 42.0 µT.

A baseball is thrown home plate at 40m/s ... the batter hits the ball and sends it flying at 60 m/s in the opposite direction. If this hit only took 0.01 seconds, then the acceleration of the ball is

A 75 kg person walking around a corner bumped directly into an 80 kg person who was running around the same corner. The momentum of the 80 kg person.

Which of the following simple machines includes a wedge? A. axe B. file C. bolt D. ramp

What are the units of speed or velocity

List the colors of visible light in order of decreasing frequency physics

You can identify a pure substance if you know it's?

A rod of mass M and length L can rotate about a hinge at its left end and is initially at rest. A putty ball of mass m, moving with speed V, strikes the rod at angle θ from the normal and sticks to the rod after the collision.