Which is true of a mechanical wave?

A) It must have a medium.

B) It must travel in empty space.

C) Both sound and light are examples.

D) It can travel in a vacuum.

When a DVD is played, a laser light hits the surface of the disk and then returns to the detector. Which wave phenomenon allows the DVD player to work? A. absorption B. interference C. reflection D. refraction

What is the kinetic energy of a 55 kilogram skier traveling at meters per second

How can a scientist ensure that his or her data are reliable?

How many atoms are represented by one formula unit of aluminum sulfite, al2 (so3) 3?

What happens to a liquid beyond its certain temperature

What happened to the test charge when brought near another positive charge, and how did you use this fact to score a goal only using positive charges? Explain for both the practice charge and more difficult levels.

You get up in the morning, get dressed, eat breakfast, walk to the bus stop, and ride to school. List three different energy transformations that have taken place.

If you lived by the sea, what effect of the moon would you see? Describe the effect.

20g of ice at 0℃ is mixed with 20g of hot water at 60℃. Then amount of water in mixture in equilibrium condition will be

A person cannot see clearly objects closer than 2.00 m from her/him. What is the refractive power (in diopters) of the correction lenses that will allow her/him to clearly see objects located 30.