Which best compares a brush and a commutator in an electric motor?

Sodium-22 Sodium-25 # of protons # of neutrons # of electrons

A guitar string is plucked. What best describes the formation and transmission of the sound wave?

A sound wave has a frequency of 684 Hz in air and a wavelength of 0.53 m. What is the temperature of the air? Assume the velocity of sound at 0◦C is 327 m/s. Answer in units of ◦C.

About how many moons are there in the solar system? A. 25 B. 50 C. 75 D. 100

Does the inertia of an object change as the object's velocity changes explain

The stored energy an object has due to its position is potential energy. True or False?

Describe two changes of state that releases energy

A student is trying to determine if a solution is acidic or basic. She does not have any litmus paper. Which would she most likely use to get a reading on her solution? vinegar soap cabbage juice aquarium water

How many grams of ice at 0°c will melt if 1.50 kj of heat are added? (the molar heat of fusion of water is 6.01 kj/mol.) 4.49 g 12.0 g 7.51 g 2.99 g?

Describe two ways of detecting black holes in space.