Dolphins communicate using compression waves (longitudinal waves). some of the sounds dolphins make are outside the range of human hearing.

upon spotting a hungry shark, dolphin a sends a message to dolphin b. to send this message as effectively as possible, dolphin a would

question 1 options:

make a softer sound because the shark will not hear the softer signal.

send the message above the water when it jumps because air is more dense than water, and the sound would be louder above the water.

send the message underwater because a more dense medium produces a louder sound.

make a higher pitched signal because a higher pitch is a louder sound.

Astudent throws a water balloon with speed v0 from a height h = 1.76 m at an angle θ = 21° above the horizontal toward a target on the ground. the target is located a horizontal distance d = 9.5 m from the student’s feet. assume that the balloon moves without air resistance. use a cartesian coordinate system with the origin at the balloon's initial position. (a) what is the position vector, rtarge t, that originates from the balloon's original position and terminates at the target? put this in terms of h and d, and represent it as a vector using i and j. (b) in terms of the variables in the problem, determine the time, t, after the launch it takes the balloon to reach the target. your answer should not include h. (c) create an expression for the balloon's vertical position as a function of time, y(t), in terms of t, vo, g, and θ. (d) determine the magnitude of the balloon's initial velocity, v0, in meters per second, by eliminating t from the previous two expressions.