Question

a disk of a radius 50 cm rotates at a constant rate of 100 rpm. what distance in meters will a point on the outside rim travel during 30 seconds of rotation?​

Answer 1

Distance travelled in one round will be equal to the circumference of the disc i.e
`2 \pi r`

Radius=50cm

Circumference=
`2 * (22)/(7) * 50cm=> (2200)/(7) cm`

If the disc rotates at speed of 100rpm that means it completes 100 rotation in a minute(60 second)

So, in 30 seconds it will complete 50 rotation.

1 rotation =
`(2200)/(7) cm`

`50 rotation=(2200)/(7) * 50cm \\\\ (110000)/(7) cm`

Break it in decimal.

Your answer will be 15714.2 cm