Which best describes longitudinal waves?
a. compressions and rarefactions make up longitudinal waves, which can only travel in matter.
b. light energy travels in longitudinal waves and can travel in either matter or empty space.
c. longitudinal waves carry sound energy and are made up of crests and troughs.

According to newton’s first law of motion, which force is expected to cause a body to accelerate?

Acharge q experiences no net force at a particular point in space. which of the following situations described below must always be true? -there are no other charges nearby. -if there are other charges nearby, they must all have the same sign as q. -if there are other charges nearby, they must all have the opposite sign of q. -if there are other charges nearby, the total positive charge must equal the total negative charge. -none of the above

An astronaut on the moon throws a baseball upward. the astronaut is 6 ft, 6 in. tall, and the initial velocity of the ball is 3030 ft per sec. the height s of the ball in feet is given by the equation s equals negative 2.7 t squared plus 30 t plus 6.5s=−2.7t2+30t+6.5, where t is the number of seconds after the ball was thrown. complete parts a and b.