AnandTech Forums Physics question: non-uniform circular motion
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 03-21-2006, 06:14 PM #1 PCMarine Diamond Member   Join Date: Oct 2002 Posts: 3,277 Physics question: non-uniform circular motion A crankshaft, with a diameter of 3.00 cm, rotating at 2200 rpm comes to a halt in 1.50 s. Q1: What is the tangential acceleration of a point on the surface of the crankshaft? I think I have to convert 2200 rpm to m/s (velocity), to find the acceleration (change in velocity/1.50s). Then divide the acceleration by the radius. However, I don't know how to do the rpm to m/s conversion. Q2: How many revolutions does the crankshaft make as it stops?
 03-21-2006, 06:19 PM #2 jagec Lifer   Join Date: Apr 2004 Location: Milky Way Posts: 24,401 Physics question: non-uniform circular motion Find the circumference of the shaft, which is easy. Now, you know the velocity at the surface is RPM * circumference (divide by 6000 to convert to m/s, by default it will be cm/min) Start with that, let us know how it goes.
 03-21-2006, 06:48 PM #3 PCMarine Diamond Member   Join Date: Oct 2002 Posts: 3,277 Physics question: non-uniform circular motion alright thanks, I got -2.30 m/s^2 for Q1
 03-21-2006, 06:51 PM #4 Eli Super ModeratorElite Member   Join Date: Oct 1999 Location: Portland, OR Posts: 50,005 Physics question: non-uniform circular motion Interesting question.. What are you studying for? __________________ http://www.bumblebeebatteries.com 2001 Honda Insight 5MT, MIMA #163P - 158,388 miles and counting as of 7/2011 Best Trip - 82.0MPG over 1200 miles 2001 Honda Insight 5MT - 450,000 miles and counting as of 2/2012 (Fiancee's) Best Trip - 92.4MPG over 400 miles 2000 Honda Insight 5MT, MIMA #173P, BCM Gauge, OBDIIC&C Gauge, Upgraded 8Ah battery - 227,248 miles and counting as of 10/2011 Best Trip - 83.1mpg over 458mi
 03-21-2006, 09:16 PM #5 PCMarine Diamond Member   Join Date: Oct 2002 Posts: 3,277 Physics question: non-uniform circular motion circular motion, specifically non uniform
 03-21-2006, 09:19 PM #6 PurdueRy Lifer   Join Date: Nov 2004 Posts: 13,837 Physics question: non-uniform circular motion for Q2..now that you have accel...you can use a simple physics equation to calculate how far it will go before it slows to 0 m/s. Divide this by the circumference