Physics help average acceleration

  • Thread starter Melchior25
  • Start date
  • #1
Melchior25
30
0
So here is the question I'm stuck on.

A woman is reported to have fallen 112 ft from a building, landing on a metal ventilator box, which she crushed to a depth of 24 in. She suffered only minor injuries.

Calculate the magnitude of her average acceleration while in contact with the box.

I know average accel. = (delta v) / (delta t)

I calculated the speed of the woman just before she collided with the box to be 84.664 ft/s.

Although I'm a bit lost on how to calculate the avg. acceleration because I'm not sure what equation I should use to calculate (t).
 

Answers and Replies

  • #2
Rudipoo
32
0
Try using one of the equations of motion which doesn't involve time, that is,

v^2 = u^2 + 2as

where v is the final velocity, u is the initial velocity, a is the average acceleration and s is the displacement between when vel = u and vel = v
 
  • #3
Shooting Star
Homework Helper
1,982
4
DELETED: gave the wrong formula by mistake. Rudipoo is right.
 
Last edited:
  • #4
Rudipoo
32
0
You need to know the accleration to find the time using the s = ut - 0/5at^2 equation, so that's no good surely, because that's ultimatley what you're trying to find. Use your initial velocity as the one you calculated, and write down what the final velocity must be. You know the displacement while in contact with the box, and thus you can find the acceleration using equation I gave above.
 

Suggested for: Physics help average acceleration

Replies
16
Views
684
Replies
1
Views
327
Replies
2
Views
549
Replies
1
Views
331
  • Last Post
Replies
12
Views
622
Replies
8
Views
1K
Replies
6
Views
661
Replies
5
Views
588
Replies
5
Views
526
Replies
7
Views
366
Top