Question 92: Motion in 1D

Question

A parachutist after bailing out falls $$50$$ $$m$$ without friction.  When parachute opens, it decelerates at $$2\,\,m/{s^2}.$$ He reaches the ground with a speed of $$3$$ $$m/s$$. At what height, did he bail out?

Accepted Answer

The velocity of parachutist when parachute opens at 50 m is
$$u = \sqrt {2gh}  = \sqrt {2 	imes 9.8 	imes 50}  = \sqrt {980} $$
The velocity at ground, $$v=3m/s$$
$$	herefore$$ $$S = {{{v^2} - {u^2}} \over {2 	imes \left( { - 2} ight)}} = {{{3^2} - 980} \over { - 4}} \approx 243\,m$$
Initially he has fallen $$50$$  $$m.$$
$$	herefore$$ Total height from where
He bailed out $$=243+50=293m$$

Answer

$$182$$ $$m$$

Answer

$$91$$ $$m$$

Answer

$$111$$ $$m$$

Answer

$$293$$ $$m$$

Motion in 1D

A parachutist after bailing out falls $50 m without friction. When parachute opens, it decelerates at 2\,\,m/{s^2}. He reaches the ground with a speed of 3 m/s$. At what height, did he bail out?

Choose the correct answer: