An echo is heard when sound is reflected off a surface. Which of the following best explains this phenomenon?

What causes a regular reflection? A. Light waves strike a rough, uneven surface at a 45 degree angle and are reflected back at a 90 degree angle. B. Parallel light waves strike a smooth, polished surface and reflect back in the same direction. C.

An electromagnetic wave is produced by: a. an accelerating charged particle or changing magnetic fields b. an accelerating uncharged particle and changing magnetic fields c. a stationary charged particle and a magnetic field d.

A cheetah runs at a steady velocity of 60 km/h (16.7 m/s). Over a period of 5.0s, the cheetah increases its pace to 95 km/h (26.4 m/s). What is the average acceleration of the cheetah over this period? must show work.

What is the part of a circuit where electrons give up most of their energy?

What is most similar about alkaline earth metals

Object A has a length of 3 cm, a width of 10 cm, and a height of 2 cm. Object B is dropped into a graduated cylinder. It displaces 60 mL of water. The volume of object A is:

Is the following sentence true or false? Some information about an object or process may be missing from a model.

If V is a velocity, l a length, and v a fluid property having dimensions of L2T-1, which of the following combinations are qualitatively dimensionless (show work for a through d) : (a) V l v (b) Vl/v (c) V2v (d) V / (l v)

What happens to the total mechnical energy of the apple as it falls from the tree?

Fair Bonus Question: Derive the equation for gravitational potential energy, starting with the definition of work.