How do we usually hear things? Sound waves are made of ___ that pushes together ___.

A. energy, air particles

B. electromagnetic waves, parts of our ear

Why does water spilled on a glass surface wets the surface

Julie throws a ball to her friend Sarah. The ball leaves Julie's hand a distance 1.5 meters above the ground with an initial speed of 18 m/s at an angle 42 degrees; with respect to the horizontal. Sarah catches the ball 1.5 meters above the ground.

A student adds 10 mL of hydrochloric acid to a 20 ml sodium hydroxide solution. What will most likely happen to the pH of the solution?

The number of protons plus the number of neutrons in an atom is called

What information can you use to calculate the empirical formula of a compound

Recall that in the equilibrium position, the upward force of the spring balances the force of gravity on the weight.

At one instant, the center of mass of a system of two particles is located on the x-axis at 2.0 cm and has a velocity of (5.0 m/s) ˆx. One of the particles is at the origin. The other particle has a mass of 0.

A 91 kg block is released at a 6 m height as shown. The track is frictionless. The block travels down the track, hits a spring of force constant k = 1968 N/m. The acceleration of gravity is 9.

Why do charges build up on clothing in an electric dryer?

Two plates with area A are held a distance d apart and have a net charge + Q, and - Q, respectively. Assume that all the charge is uniformly distributed on the inner surfaces of the plates.