Which of the following statements is
true of sound transmission through various
mediums?
a. sound insulators prevent sound from
being transmitted better than elastic solids.
b. inelastic materials conduct sound
better than elastic solids.
c. elastic solids prevent sound from
being transmitted better than liquids.
d. gases conduct sound better than
liquids.

The man of mass m1 and the woman of mass m2 are standing on opposite ends of the platform of mass m0 which moves with negligible friction and is initially at rest with s = 0. the man and woman begin to approach each other. derive an expression for the displacement s of the platform when the two meet in terms of the displacement x1 of the man relative to the platform.

Aballoon is rising vertically upwards at a velocity of 10m/s. when it is at a height of 45m from the ground, a parachute bails out from it. after 3s he opens his parachute and decelerates ata a constant rate 5m/s.when. (a) what was the height of the parachutist above the ground when he opened his parachute? (b)how far is the parachutist from the balloon at t=3s? (c)with what velocity does the parachutist hit the ground? (d)after how long does the parachutist hit the ground after his exist from the balloon?

Atoy airplane, flying in a horizontal, circularpath, completes 10. complete circles in 30.seconds. if the radius of the plane’s circular pathis 4.0 meters, the average speed of the airplane is(1) 0.13 m/s (3) 1.3 m/s(2) 0.84 m/s (4) 8.4 m/s