Question

A skier (m=57.0 kg) starts sliding down from the top of a ski jump with negligible friction and takes off horizontally. If h = 6.20 m and D = 13.4 m, find H.

Answer 1

what is "h" ?

Answer 2

Use the energy method.
Decrease in potential energy= gain in kinetic energy

mg(H-h) = 1/2 mv^2 here we get the velocity.

After taking off, the range is given by

R= u. t where "t" is the time of descent and 'u' is the velocity.

Answer 3

Hope its clear

Answer 4

(1/2)mv^2=mgD so v=sqrt(2gD)
v on above is v0 for next part of ask (when skier leave ski jump)
y=(v0^2/2*g) so H=y+h

Answer 5

isn't "d" the distance covered after he jumped?

Answer 6

i think D is ski jump's length

Answer 7

i drew above do you solve it?

Answer 8

D should be the range i feel.

Answer 9

Let us take D to be the range.
Now, decrease in potential energy would be mg(H-h) as he came down a height of H-h

So, mg(H-h) = 1/2 mv^2

v=(2g(H-h))^1/2

Answer 10

question want H did you get it?

Answer 11

yes.

Answer 12

so it is...?

Answer 13

approximately 15.026

Answer 14

how did you get time of descent

Answer 15

t= {2h/g}^1/2

Answer 16

this t is time of H time of descent is: 2*t

Answer 17

how did you take v=u in two formula?
mg(H-h) = 1/2 mv^2
R= u. t

Answer 18

D= v. t where v= [2g(H-h)]^1/2 and t= [2h/g]^1/2
"t' is the time of descent from "h" to the ground.

I typed u instead of v

Answer 19

u is velocity of body when it's arrive to ground but vis velocity in top of path

Answer 20

no i think you use 2*t in formula for D

Answer 21

hence d is all of horizontally path

Answer 22

"v' is the velocity of the man before taking off. We are not concerned about the velocity which he will have while landing on the ground

Answer 23

Yes "D" is the horizontal distance covered.

Answer 24

did you see my diagram ? H is max height that man arrive . i didn't understand your fig

Answer 25

i mean that how did you yeild to u=v

Answer 26

When a body takes off horizontally, the height from which it took off will be the maximum height. i took that the person slides from a height "H" and after reaching a height "h', he takes off and covers a horizontal distance 'D".

I mistyped u or v.

Answer 27

mistyped u for v

Answer 28

am i clear?

Answer 29

yes you'r right