Check your math there Paul

Posted by Check your math there Paul on Jun 15, 2002 at 13:36
(208.58.229.219)

Re: the two forms of energy in question here. (paul baughn)

You state:

if the 100 kg mass moves a distance of 10 meters in 1 second the knietic energy of the moving mass would be.
ke=1/2mv^2= 50 kg * 10 = 500 J

That is incorrect because after 1 second, the mass has not yet fallen 10 meters. It would take 1.41 seconds for that.

d = .5gt^2

We know d is 10 meters and we'll round g to 10 as well so...

10 = .5 * 10 * t^2

10 = 5t^2

10/5 = t^2

2 = t^2

sqr(t) = 1.4

So, how fast is the mass travelling after 1.4 seconds?

V = gt

V = 10 * 1.414...

v = 14

Now, finding Ke

ke = .5 * 100 * 14.14^2

Ke = 50 * 200

Ke = 1000

sorry



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