(Untitled)

[timbobimbo]

If you roll a bowling ball down the alley (assuming it rolls straight), when it begins rolling without sliding it will be moving at 5/7 its original velocity.

Comments

[a_conquistador]

What is the velocity of the bowling ball after it has completed its arc through the air, after leaving Samantha's hand and crashing into the floorboards?

[timbobimbo]

0.00000000000000001 m/s

[sarahwsmom]

There are a lot of assumptions in that statement.

[timbobimbo]

1)smooth floor+ bowling ball
2)center of mass at geometric center
3)ball rolls straight

but valid assumptions!

[linked2zelda]

*bobbitt* no, that's invalid, you're assuming that there are no alien invasions that inturrupt the gravitational fields present, it's wrong.

real MAN'S MATH

[questions4u]

i've been waiting 4 u to show off ha

i may be wrong ... you're the one at mit here

[chaddd]

V = initial velocity
v = velocity upon rolling

KE = KE + RE

(1/2)mV^2 = (1/2)mv^2 + (1/2)Iw^2
= (1/2)mv^2 + (1/2)[(2/5)mR^2](v^2/R^2)
= (1/2)mv^2 + (1/5)mv^2
= (7/10)mv^2

so (1/2)V^2 = (7/10)v^2
v^2 = (1/2)V^2/(7/10)
v^2 = (5/7)V^2

v = Sqrt(5/7)V

Tell me if i did something dumb...

Re:

[timbobimbo]

But remember kinetic energy isn't conserved; what's making it start to roll is torque from friction opposing the initial velocity.

Re:

[chaddd]

yeah i'm not saying KE is conserved, the torque from the friction on the ball goes into rotational energy RE right?

[shalando_27]

oh chad...if only you could use that formula to get my sister... haha justttt kidding!

velocity

[goingboeing]

This is great. Now that you're at MIT maybe you can answer a question that has perplexed thousands for decades. What IS the airspeed velocity of an unladen swallow?

Re: velocity

[timbobimbo]

hahahahahahahahahahhahhahahahahahaha

african or european?

Re: velocity

[goingboeing]

Don't get me started....

Did you feel the earthquake?