Solving Velocity After Falling 268 Feet

  • Thread starter kevindpalmer2
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In summary, the correct method to calculate the speed of an average person falling from 268 feet without considering resistance is to use the equation vf^2 = vi^2 + 2*a*d, where vf is the final velocity, vi is the initial velocity (which is 0 in this case), a is the acceleration due to gravity (9.81 m/s^2 or 32.19 ft/s^2), and d is the distance fallen (268 feet or 81.69 meters). After solving for vf, it can be converted to miles per hour by multiplying by 2.24, resulting in a final speed of approximately 93.9 mph.
  • #1
kevindpalmer2
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Homework Statement



Trying to figure how fast you would be falling after 268 feet? not worrying about resistance and in terms of weight just and average person... this is what I did.. is it correct? or way off


vf^2 = vi^2 + 2*a*d
vf^2 = 0 + 2* 9.81 * 90
vf^2 = 1765.8m^2/s^2
take square root
vf = 42 m/s then convert to mph multiply by 2.24? 93.9mph

Homework Equations



vf^2 = vi^2 + 2*a*d
vf^2 = 0 + 2* 9.81 * 90
vf^2 = 1765.8m^2/s^2
take square root
vf = 42 m/s then convert to mph multiply by 2.24? 93.9mph

The Attempt at a Solution


vf^2 = vi^2 + 2*a*d
vf^2 = 0 + 2* 9.81 * 90
vf^2 = 1765.8m^2/s^2
take square root
vf = 42 m/s then convert to mph multiply by 2.24? 93.9mph
 
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  • #2
That's the correct method. Some of your conversion factors seem to have small errors

90 m ≈ 295.3 ft and 268 ft ≈ 81.69 ft.

etc.

If you want to do it all in US Customary Units, g = 9.81 m/s2 ≈ 32.19 ft/s2.
and
60 mph = 88 ft/s
 

1. How do I calculate velocity after falling 268 feet?

The formula for calculating velocity after falling is v = sqrt(2gh), where v is velocity, g is the acceleration due to gravity (9.8 m/s^2), and h is the height of the fall. Plugging in the values, we get v = sqrt(2*9.8*268) = 73.54 m/s.

2. What is the acceleration due to gravity?

The acceleration due to gravity is the rate at which an object falls towards the ground due to the force of gravity. On Earth, it is approximately 9.8 m/s^2 (meters per second squared).

3. Can I use a different unit of measurement for height?

Yes, as long as the unit is consistent with the unit used for acceleration due to gravity. For example, if using feet for height, the acceleration due to gravity should also be in feet per second squared.

4. Does air resistance affect the calculation of velocity after falling?

Yes, air resistance can affect the calculation of velocity after falling. However, for relatively short distances like 268 feet, the effect of air resistance is minimal and can be ignored.

5. How can I use velocity after falling to determine the time of fall?

The time of fall can be calculated using the formula t = sqrt(2h/g), where t is time, h is the height of the fall, and g is the acceleration due to gravity. Plugging in the values, we get t = sqrt(2*268/9.8) = 5.54 seconds.

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