Which phrase gives the correct definition for destructive interference? A. when a wave appears to be at a standstill and vibrates in place

B. when the trough of one wave matches the crest of another

C. when two waves with identical crests and troughs meet

D. when energy reflects back toward its source

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?