PLEASEPLEASEPLEASE HEL what information does a ship's sonar device use to determine the distance to the ocean?
a. the speed of sound in water and the time it takes for a signal to return
b. the temperature of the water and the temperature of the air above it
c. the composition of the ocean floor and the temperature of water near the ocean floor
d. the composition of the ocean floor and the temperature of water near the ocean floor
( i know there are two of the same answers but um that's how it was so)

As you are trying to move a heavy box of mass m, you realize that it is too heavy for you to lift by yourself. there is no one around to , so you attach an ideal pulley to the box and a massless rope to the ceiling, which you wrap around the pulley. you pull up on the rope to lift the box. use g for the magnitude of the acceleration due to gravity and neglect friction forces. once you have pulled hard enough to start the box moving upward, what is the magnitude f of the upward force you must apply to the rope to start raising the box with constant velocity? express the magnitude of the force in terms of m, the mass of the box.

Which of the following is the phase that results when the moon is on the opposite side of the earth from the sun? a. quarter moon b. crescent moon c. new moon d. full moon

Which of these is constant for all types of electromagnetic radiation in a vacuum? select one: a. wavelength b. frequency c. photon energy d. amplitude e. velocity