Question

For a movie scene, an 85.0 kg stunt double falls 12.0 m from a building onto a large inflated landing pad. After touching the landing pad surface, it takes her 0.468 s to come to a stop. What is the magnitude of the average net force on her as the landing pad stops her?

Answer 1

2785.43N

Step-by-step explanation:

According to Newton's second law;

`F=(m(v-v_1))/(t_1)..............(1)`

Given;

m = 85kg,
`t_1=0.468s`

v is the velocity with which she lands on the pad while
`v_1` is her final velocity as she comes to rest. Hence
`v_1=0m/s`

We obtain v from first equation of motion under gravity as follows;

`v=u+gt..........(2)`

u = 0 and
`g=9.8m/s^2`

hence;

v = 9.8t...........(3)

t is the time taken for her to fall through the height h = 12m, so we use the second equation of motion to find it as follows;