The change in pitch of a train's horn as it passes while you are standing still can be explained by

a. sympathetic vibration.

b. ultrasonic vibrations.

c. resonance.

d. the Doppler effect.

What is the density of an object with a mass of 60g and a volume of 2cm3?

An atom of 6/2 He decays by beta decay. What atom is left after decay

Which process produces rising air when mountains push the air upward? A. orographic lifting B. localized convective lifting C. frontal wedging D. convergence

How is a ground wire a safety precaution

Would objects fall faster on Mars or on Earth? Why?

Which statement is correct about gasoline when it is burned? Heat energy is created by the gasoline. The total energy of the gasoline decreases. Chemical energy in the gasoline is destroyed. Chemical energy is transformed into heat energy.

The tilt of the Earth's axis of rotation changes over a period of 41,000 years. Which of these statements best predicts a long term effect of the changes in the tilt of the Earth's axis of rotation? a. The Earth's climate would change. b.

What do keratinized cells form?

Explain why Planck's introduction of quantization accounted for the properties of black-body radiation.

How and which waves travel either through a medium or a vacuum?