A velocity vs. time graph for an object is shown. Which parts of the graph represents the object moving
at a constant, positive acceleration?
Velocity vs Time
25
20
O W and X
O X and Y
O Y and Z
W and Z
Y
х
15
Velocity (m/s)
10
Z
N
5
w
2
4
5
3
Time (s)

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?