# Help with rotation about a fixed axis

hey..i have a problem that states. a record has an angular speed of 34.6 rev/min. Find its Angular speed in rad/s.

do you think you can help me?

Also, i have some problems dealing with a ball at the end of the string with length 1.8m. It is in horizontal circle at constant speed. IT makes 3.4 rev/s. I need to find the period of the ball's motion, the frequency, and its angular velocity...but everything i have tryed has failed.
I tryed 1.848 and .18726 for the period but was wrong. i tryed 5.34 and .5411 for the frequency but was wrong and the velocity i also got wrong.

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alexhavak said:
i have a problem that states. a record has an angular speed of 34.6 rev/min. Find its Angular speed in rad/s.
What do you think the answer should be? If the angular speed is 3.623 radians/second, and the time is given as 0.717 seconds, how do you think you would get the angle in radians? (Hint: Angle is similar to distance, which equals rate X time.)

Also, i have some problems dealing with a ball at the end of the string with length 1.8m. It is in horizontal circle at constant speed. IT makes 3.4 rev/s. I need to find the period of the ball's motion, the frequency, and its angular velocity...but everything i have tryed has failed.
I tryed 1.848 and .18726 for the period but was wrong. i tryed 5.34 and .5411 for the frequency but was wrong and the velocity i also got wrong.
Don't just give your answers, show how you got those answers. (Then we can see where you made a mistake.) Here's a hint: I assume you know that period means the time for one revolution. If you know that 3.4 revolutions takes 1 second, how long will 1 revolution take?

Fermat
Homework Helper
It has an angular velocity of 3.623 rad/sec. that means that,

in 1 sec it travels through an angle of 3.623 radians
so, in 0.717 secs it travels through an angle of ???

For the 2nd problem, convert your angular velocity from rev/s to rad/s