Question

A pole-vaulter of mass 61.8 kg vaults to a height of 4.1 m before dropping to thick padding placed below to cushion her fall.

(a) Find the speed with which she lands. Neglect any horizontal velocity she may have.
(b) If the padding brings her to a stop in a time of 0.60 s, what is the average force on her body due to the padding during that time interval

Answer 1

Step-by-step explanation:

Given

mass of Pole-vaulter
`m=61.8 kg`

height attained
`h=4.1 m`

(a)Speed at which she lands will be given by conserving Energy

i.e.
`mgh=(1)/(2)mv^2`

`v=√(2gh)`

`v=√(2* 9.8* 4.1)`

`v=8.96 m/s`

(b)she stops in t=0.6 s

`F_(avg)` is given by change in momentum in given time

`F_(avg)=(\Delta P)/(\Delta t)`

`F_(avg)=(61.8* 8.96)/(0.6)`

`F_(avg)=922.88 N`