IIT JEE , AIEEE Forum - Physics , Mechanics

saurabhkrisna

i want to ask that if a body is under free fall then its acc. is constant...........and the mass also ..................therefore the force on the body falling should be also constant....................but ,....then why a man falling from 10th floor dies and a man falling from 2 feet has a very small jerk......

sam26kal

hey
d acc is ntt constant if u resolve into 2 components
vertical n horizontal den acc along d horizontal is costant
where as along d vertical component it keeps on incresing.. dat it changes dats y a man faaling frm 10 th floor dies wherea frm 10 ft one doesntt
hope dat clears ur dbtt
i think dis cud b d possible ans
plzzzzzzz rate if right n satisfied

krishna.gopal

When a person falls from 10th floor and dies it is not because of acceleration during the free fall. After free fall when body comes in contact with earth it has to stop suddenly. Now it must come to rest in very small time. In this case acc and orce depends on change in velocity and this change is very large for man falling from 10th floor and that is why he dies

aaabothra

aaabothra

waterdemon

See this is simple.

The only role the acceleration plays in your case is

of increasing the velocity.

When the person falls from 10th floor he dies and

a the person that falls from 2nd feels a jerk bcoz

The height from where the person dies is much more than from where he gets a jerk,

F=ma you are correct but

s=dv/dt change in velocity wrt time

S and dv will vary but dt(for body to stop) will be

the same.

mass does not change.

when the person falls from 2nd floor he attains not

much velocity. (V²=2gH , as U=0)

But when the person falls from 10th floor he has

greater velocity than the one falling frm 2nd floor.

As H is more.

Since when both come at ground the velocity of

both becomes zero in same time interval but in

case of the person falling from 10th floor the change in veloctiy is very high as compared to

the person falling from 2nd floor.

So person falling from 10th floor dies whereas

one falling from 2nd feels a small jerk.

Hope you understood.

plZ rate me for my efforts.

Cheers!!!!!!!!!!!!!

spideyunlimited

in case of collisions, dont consider the force as the main factor,,, it is the momentum... mv . and as 10th floor is much higher therefore velocity increases much more than that if u fell from 2nd floor thus momentum is greater upon hitting the ground and hence higher impact

spideyunlimited

momentum increases much more when falling from higher height as time of free fall is greater

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