OT: Homework Question?

kruser · Apr 19, 2012

An object (assume not a feather, etc) is dropped from 576 feet.
How long does it take to hit the ground (no air resistance).

Dottir"s extra credit question - "seems" like I could have solved this about ?? years ago

bjb in TX from Ne · Apr 19, 2012

If I recall:

D(t)=D_0 + v_0*t + a*t^2

If your relative position is the ground 576ft below
Then D(t)=0
D_0= 576
v_0= 0
a= -32.2 ft/s^2
Solve for t

bjb in TX from Ne · Apr 19, 2012

btw Even a feather would fall at the same rate assuming no air resistance

Beatles65 · Apr 19, 2012

Here is what I remember from Junior Year High School Physics. The earths gravitational pull is 9.8m/s^2. So wouldn"t you take the 576 and divide that by the gravitational pull and get roughly 58.78 seconds until impact with the ground. Not sure if that is correct or not, but we used 9.8m/s^2 in most all the equations that we did in that class. That was four years ago so I may be off.

From Denton, Nebraska.
Andrew Kean

Owen Aaland · Apr 20, 2012

(quoted from post at 00:15:08 04/20/12) Here is what I remember from Junior Year High School Physics. The earths gravitational pull is 9.8m/s^2. So wouldn"t you take the 576 and divide that by the gravitational pull and get roughly 58.78 seconds until impact with the ground. Not sure if that is correct or not, but we used 9.8m/s^2 in most all the equations that we did in that class. That was four years ago so I may be off.

From Denton, Nebraska.
Andrew Kean

Are you using a parachute? That's only about 10 feet per second. I believe the correct answer is about 6 seconds.

SKYBOW · Apr 20, 2012

D=(.5G)(T SQUARED)
T SQUARED=D DIVIDED BY (.5G)
G IS ACCELERATION OF GRAVITY 32.17 FT/SEC SQUARED

T SQUARED =576FT DIVIDED BY .5 X 32.17 FT/SEC SQUARED

T = 5.98 SECONDS

Hendrik · Apr 20, 2012

With respect, you should not mix units, like in dividing 576 ft by 9.8 m/s^2.
Skybow has it correct.

bjb in TX from Ne · Apr 20, 2012

Look at what happens when you don't do a physics problem in 6 years... I forgot about the 1/2 on the at^2 :S

JOHNNYfromMI · Apr 20, 2012

Not very long!

glennster · Apr 20, 2012

well kruser, the last time i fell off the crib roof, it seemed like i kinda floated down in slow motion, but i hit the ground like a beef samwich. the higher up the roof ya fall off of, the longer it takes for the pain to go away.......just sayin!! hope that helps dotters!!!

James Howell · Apr 20, 2012

Only attended 11 grades back in the day and Physics for Dummies was not offered; however, think its something called <a href="http://en.wikipedia.org/wiki/Gravitational_acceleration">graveltational excelerator</a>.

James Howell · Apr 20, 2012

Was cutting limbs on Wednesday and a pine limb knocked me off the ladder.

Chainsaw hit the ground before I did, but I landed on my feet just like a cat.

Don't understand why chainsaw landed first because I weigh more than the chain saw and I'm taller.

Need some help figuring this one out!

Nancy Howell · Apr 20, 2012

We"ll talk about this when you get here.

CLTX · Apr 20, 2012

Uh-oh, you"re in trouble now!

Philip Doolittle · Apr 20, 2012

Devide distance by 32 and you will be very close.

eye4iron · Apr 20, 2012

So where do you live that there is no air resistance?

northvale · Apr 20, 2012

acceleration due to gravity is 32 ft per second squared, meaning, at the end of the 2nd second, it is moving 64 ft per second.

OT: Homework Question?

kruser

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bjb in TX from Ne

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bjb in TX from Ne

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Beatles65

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Owen Aaland

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SKYBOW

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Hendrik

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bjb in TX from Ne

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glennster

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James Howell

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James Howell

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Nancy Howell

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CLTX

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