) Ana and Dana were at the beach enjoying the waves. Remembering what they learned in science class, Ana said that the ocean waves were mechanical waves, but Dana said they were electromagnetic waves. Which student is correct and why?
A.
Both of them are right. Ocean waves travel through a medium so it is a mechanical wave. It is also an electromagnetic wave since the particles moves up and down.

B.
Only Ana is right. Ocean waves travel must have a medium to travel through so it is a mechanical wave.

C.
Only Dana is right. In ocean waves the particles move up and down which is the characteristic of an electromagnetic wave. Ocean waves need a medium so it is not a mechanical wave.

D.
Both of them are wrong. Neither ocean waves nor EM waves need a medium.

Asample of a gaseous substance changes into a liquid

1point) a skydiver weighing 130 lb (including equipment) falls vertically downward from an altitude of 14,000 ft and opens the parachute after 20 s of free fall. assume that the force of air resistance, which is directed opposite to the velocity, is of magnitude 0.85|v|0.85|v| when the parachute is closed and is of magnitude 17|v|17|v| when the parachute is open, where the velocity vv is measured in ft/s. assume that acceleration due to gravity has magnitude 32 ft/s/s; remember that weight is the product of mass and gravitational acceleration. find the speed of the skydiver when the parachute opens. speed is 150.6121788 ft/s find the skydiver's height when the parachute opens. height is 2338.98591 ft find the limiting velocity vlvl after the parachute opens. (think about whether this should be positive or negative.) vl=vl= 7.647 ft/s

Which of the following is not a characteristic of s waves? a. travel slower than p waves. b. cannot be detected in locations more than 105° from an earthquake’s epicenter. c. travel through solids and liquids. d. only affect coastal regions.