- #1

- 4

- 0

- Thread starter Mmats
- Start date

- #1

- 4

- 0

- #2

- 46

- 0

try finding your momentum when youve reached your final velocity

- #3

russ_watters

Mentor

- 19,878

- 6,297

It depends on how fast you decelerate when you hit the ground.

- #4

- 4

- 0

I would round it off to instantly, no? Just imagine my legs being perfectly straight as i hit the ground..russ_watters said:It depends on how fast you decelerate when you hit the ground.

- #5

- 863

- 4

Thing is, when you lose momentum like this, you exert what is called an impulse, or force * time. If you decelerate instantly, that means you exert an infinitely large force for an infinitely small period of time.Mmats said:I would round it off to instantly, no? Just imagine my legs being perfectly straight as i hit the ground..

- #6

- 4

- 0

3.048m/s * 68.04kg = 207.38 kg m/s

so the scale would read 207.38kg?

so the scale would read 207.38kg?

- #7

russ_watters

Mentor

- 19,878

- 6,297

No. Notice that your units don't match...

- #8

jtbell

Mentor

- 15,642

- 3,689

If it takes you one second to slow to a stop, the average force that the ground exerts on you is 207.38 N. If it takes 0.1 second, the average force is 2073.8 N. If it takes 0.01 second, the average force is 20738 N. And so forth.Mmats said:3.048m/s * 68.04kg = 207.38 kg m/s

- #9

- 4

- 0

- #10

- 500

- 0

- #11

Andrew Mason

Science Advisor

Homework Helper

- 7,634

- 368

You would need to know the spring constant of the scale, then use:Mmats said:

[tex]mgh = \frac{1}{2}k(\Delta x)^2[/tex]

where [itex]\Delta x[/itex] is the displacement of the spring from its equilibrium position when you are just standing on it. This gives:

[tex]\Delta x = \sqrt{2mgh/k}[/tex]

You would then add mg/k (the spring extension due to your weight when just standing on it) to that to find the maximum displacement.

So:

[tex]F = k\Delta x + mg = \sqrt{2mghk} + mg[/tex]

The higher the spring k, the higher the force.

AM

- Replies
- 1

- Views
- 3K

- Last Post

- Replies
- 35

- Views
- 2K

- Replies
- 15

- Views
- 2K

- Last Post

- Replies
- 2

- Views
- 10K

- Last Post

- Replies
- 8

- Views
- 2K

- Last Post

- Replies
- 1

- Views
- 1K

- Last Post

- Replies
- 1

- Views
- 5K

- Last Post

- Replies
- 3

- Views
- 2K

- Replies
- 3

- Views
- 774

- Replies
- 4

- Views
- 5K