Question

1.
A parachutist jumps out of an airplane and accelerates with gravity for 6 seconds. He then pulls the
parachute cord and after a 4 s deceleration period, descends at 10 m/s for 60 seconds, reaching the
ground. From what height did the parachutist jump? Assume acceleration due to gravity to be
10 m/s2 throughout the motion.
(A) 840 m
(B) 920 m
(C) 980 m
(D) 1020 m
-ndafunlimlho is lowed down uniformly to 30 km/hr for repair purposes
​

Answer 1

hey,hope this helps,

At the first, u=0m/s, a=g,v1=?

this v1 is the final velocity after 6 s.

x=0.5×10×6×6=180m.

Again, x is the displacement after 6 s.

Then,v1=60m/s.

Also after 4s it has completed y m.

y=60×4+0.5×10×16=320m.

at the final moment,

the acceleration is again for 10m/s² as mentioned in the question.

so v2 is the final velocity after 4s before the final moment.

as v2=2×10×500=100m/s.

Then, final height=100×60+0.5×10×(60)²=9600m.

hence total height=9600+500=10100m.

ur welcome