Does the Average Speed Formula Work for Rolling Objects?

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The discussion centers on the calculation of kinetic energy for a rolling ball bearing down a slope, where the contributor notes discrepancies between the sum of kinetic energies (translational and rotational) and the potential energy. The contributor calculated the translational kinetic energy as 0.002520831 and rotational kinetic energy as 0.001008332, totaling 0.003529163, which is significantly lower than the potential energy of 0.014278472. A key point raised is the potential impact of slipping on these calculations. A response highlights that using average speed (distance divided by time) is inappropriate since the ball is accelerating, suggesting the need for instantaneous speed for accurate results. The discussion emphasizes the importance of correct speed calculations in energy conservation equations for rolling objects.
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when i add ke translational + ke roatational, i don't get potential which i should, although i was wondering if maybe it was due to slipping although i thought it would still be closer than i got

does this sound right?

ke trans(0.002520831)+ke rotational (0.001008332) = 0.003529163
and
pe=0.014278472

as you can see not very near it!

is this right or have i gone wrong?

the exp was rolling a ball bearing down a 5 degree slope and these calcs were from the 1m release mark. the radius is 0.00765m


thanks

to get the angular speed i used linear V/R (radius)

i got linear v by divinding distance by time.
 
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alex_boothby said:
when i add ke translational + ke roatational, i don't get potential which i should, although i was wondering if maybe it was due to slipping although i thought it would still be closer than i got

does this sound right?

ke trans(0.002520831)+ke rotational (0.001008332) = 0.003529163
and
pe=0.014278472

as you can see not very near it!

is this right or have i gone wrong?

the exp was rolling a ball bearing down a 5 degree slope and these calcs were from the 1m release mark. the radius is 0.00765m


thanks

to get the angular speed i used linear V/R (radius)

i got linear v by divinding distance by time.

If you are rolling a ball down a slope, the linear v will NOT be d/t because the ball is accelerating. d/t is average speed not instantaneous speed, which is what you need for your equations.

-Dan
 

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