a parachutist dropped freely from helicopter for 20 seconds before the parachute opens out . then he descends with retardation of 40 m per second square . the height of the helicopter from the ground level is 2500m. when he drops out, his velocity on reaching the ground will be
a)10
b)20
c)
d)zero
Answers
Answered by
75
The correct option is: (d) v= 0m/s.
The initial velocity of the parachutist is zero
now V=u+gt
V=0+(-10)20
V=-200 (-sign as the velocity is in downward direction)
Now S=ut+1/2ut^2
so S=0+1/2(-10)*400
S=2000
Now H=2500-2000
=500
Now v^2=u^2+2ah
v^2=40000-(2*40*500)
v^2=0
v=0 m/s.
The initial velocity of the parachutist is zero
now V=u+gt
V=0+(-10)20
V=-200 (-sign as the velocity is in downward direction)
Now S=ut+1/2ut^2
so S=0+1/2(-10)*400
S=2000
Now H=2500-2000
=500
Now v^2=u^2+2ah
v^2=40000-(2*40*500)
v^2=0
v=0 m/s.
serena777:
v^2=u^2+2 (-a)(-s)
Answered by
31
Answer:
the answer is zero m/s
Explanation:
plz see into the pic..
hope it helps..
cheers..
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