Which law explains why a book flying in the air hitting a person would hurt more than a feather hitting a person?

When a sound wave moves through a medium such as air, the motion of the molecules of the medium is in what direction (with respect to the motion of the sound wave) ? Group of answer choicesa. Perpendicularb. Parallalc. Anit-paralleld.

Two stars have proper motions of one arcsecond per year. Star A is 20 light-years from Earth, and Star B is 10 light-years away from Earth. Which one has the faster velocity in space?

A hydrogen atom has a diameter of about 10 nm. a. Express this diameter in meters. b. Express this diameter in millimeters. c. Express this diameter in micrometers.

A cylindrical tube 14.0 cm high and 2.5 cm in diameter is used to collect blood samples. how many cubic decimeters (dm3) of blood can it hold (v of a cylinder = r2h) ?

A person began running due east and covered 15 km in 2.0 hr. What is the average velocity of the person? (Hint: v = d/t) Show all your work!

Suppose that the entire Universe began to contract (collapse) right now. Five billion years from now, an astronomer looking at the spectra of galaxies. What would be the changes noted? A.

Which of the following statements about the atom is false?

Explain why models are often used to study other planets.

The main factors that affect an area's temperature are prevailing winds and mountains. a. True b. False

What is the displacement of an object during a specific unit of time?