Welcome to PHY 121 Blog Help. Here's how it works. For each homework question and lab report we will make a post, this will probably contain a few tips on what the problems are about and how to solve them. If you are stuck on something then instead of emailing us directly you should post a comment in reply to the relevant post. We will try to guide you through tough points and help you understand the problems and the concepts behind them.
Saturday, September 25, 2010
Ch5_1 #2
Convert the rpm (= revolutions per minute) into radians/sec. Multiplying by t gives you the angle swept through in radians. What do you have to do with the initial angle ? Don't forget that the problem asks for an answer between 0 and 2pi.
6 comments:
Anonymous
said...
I think I have everything right except I have forgotten how to express the final answer between 0 and 2pi. can someone help me?
Help! I have converted from rpm to rads/sec and I have the velocity (I guess0 in rad /sec/ when I multiply by the time, I get radians. What do I do from here?
Ok, so I converted 76rpm to 7.95 rad/sec then multiplied by 8.0sec and got 63.6rads. Added the initial angle 0.45 rad to get 64.05. Divided that by 2pi...and it's wrong! What am I doing wrong????
When the final answer is between 0 and 2pi, that means your answer must be between 0 and 6.283.
RPM stands for revolutions per minute. 1 revolution means to go around a circle 1 time. A circle has 2pi radians.
When you have the rad/sec, you can find how many times the turntable has rotated. Remember, whether it turns 1 time, 5 times, or 1000 times, it will end up at the original position, as long as the number of turns is a whole number. Remember, your answer must be between 0 and 6.283.
6 comments:
I think I have everything right except I have forgotten how to express the final answer between 0 and 2pi. can someone help me?
how do you convert rpm into radians/sec..thanks
how many revolutions are in a radian?????????????????????????
Help! I have converted from rpm to rads/sec and I have the velocity (I guess0 in rad /sec/ when I multiply by the time, I get radians. What do I do from here?
Ok, so I converted 76rpm to 7.95 rad/sec then multiplied by 8.0sec and got 63.6rads. Added the initial angle 0.45 rad to get 64.05. Divided that by 2pi...and it's wrong! What am I doing wrong????
When the final answer is between 0 and 2pi, that means your answer must be between 0 and 6.283.
RPM stands for revolutions per minute. 1 revolution means to go around a circle 1 time. A circle has 2pi radians.
When you have the rad/sec, you can find how many times the turntable has rotated. Remember, whether it turns 1 time, 5 times, or 1000 times, it will end up at the original position, as long as the number of turns is a whole number. Remember, your answer must be between 0 and 6.283.
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