Homework Help: Physics- drwls please help

Posted by Mary on Wednesday, March 14, 2007 at 1:48am.

A certain CD has a playing time of 80 minutes. When the music starts, the CD is rotating at an angular speed of 4.8 x 10^2 revolutions per minute (rpm). At the end of the music, the CD is rotating at 2.1 x 10^2 rpm. Find the magnitude of the average angular acceleration of the CD. Express your answer in rad/s2.

(0.104667 x -2.7) / (80 x 60)=
-0.000058875

[270 rev/min* 2 pi rad/rev* 1/60 min/sec]/(4800 sec) = 5.89*10^-3 rad/sec^2

You forgot the 10^2 multiplier on the rpms.

drwls the system is telling me the answer is incorrect. I saw where my I made the mistake and corrected it but it is still wrong. The answer I came up with is -0.00589 rad/sec^2.

You are right about the minus sign, since it is decelerating. Maybe they want you to use only two significant figures (-5.9*10^-3). Other than that, I don't see why it is getting marked wrong.

Physics- drwls please help - Amber, Wednesday, July 16, 2008 at 3:09pm
I had this prob with different numbers. it wants the answer in scientific notation. mine was 6.5E-3

Answer this Question

Related Questions

Physics - A certain CD has a playing time of 76 minutes. When the music starts, ...
physivs - A certain CD has a playing time of 68 minutes. When the music starts, ...
Physics - ) Joe has a playing time of 74 minutes. When the music starts, the CD ...
Physics - 3) Joe has a playing time of 74 minutes. When the music starts, the CD...
Physics - A certain CD has a playing time of 80 minutes. When the music starts, ...
7th Grade Math - What is the radius of a CD in cm? What\'s the height of a ...
Physics - A CD rotates at 500 (revolutions per minute) while the last song is ...
physics - A CD has a mass of 17.4 g and a radius of 6.01 cm. When inserted into ...
physics - A CD has a mass of 17.4 g and a radius of 6.01 cm. When inserted into ...
Physics - A CD has a mass of 17.0 g and a radius of 5.98 cm. When inserted ...

For Further Reading

First Name:
School Subject:
Answer: