## ksaimouli Group Title a compact disc has a radius of 6cm if the disc rotates about its central axis at a constant angular speed of 5 rev/s what is the total distance traveled by a point on the rim of the disc 40min one year ago one year ago

1. ksaimouli Group Title

when i did $\omega=\frac{ \theta }{ t }$

2. ksaimouli Group Title

3. ksaimouli Group Title

it did not work

4. Shane_B Group Title

This question doesn't even require physics...it's purely mathematical: First, calculate the circumference of the circle. Then multiply that by 5 since it makes 5 revolutions per second. That will give you how far the dot traveled in 1 second. Then just multiply that times how many seconds are in 40 minutes.

5. ksaimouli Group Title

Can u show me in physics way

6. Vincent-Lyon.Fr Group Title

$$\omega=\frac{ \theta }{ t }$$ is ok. You should just be careful to plug in the values in the right units.

7. ksaimouli Group Title

but @Vincent-Lyon.Fr i did not get the answer with this equation

8. Vincent-Lyon.Fr Group Title

Show us you numbers.

9. ksaimouli Group Title

$\theta=10\pi(2400)$

10. Vincent-Lyon.Fr Group Title

What the question asks is the DISTANCE travelled, not the angle swept during that time.

11. ksaimouli Group Title

Distance in rotation is nothing but the angle right?

12. Vincent-Lyon.Fr Group Title

No, distance is distance (in metres), and angle is angle (in radians).

13. ksaimouli Group Title

so i found theta so can i use s=r theta

14. ksaimouli Group Title

$s=r \theta$

15. Vincent-Lyon.Fr Group Title

Yep and you should find about 4.5 km