(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

In an old record player, the flat round vinyl disc (record) is placed on a turntable which spins around. Once it gets going around and around, it moves so that the number of revolutions it makes per minute is constant (33 and 1/3). An insect settles on the edge of the spinning record. It decides to crawl in a straight line to the centre of the record.

a) draw the actual path the insect makes as seen by you the observer

b)If the insect moves from the edge to the centre (a distance of 15 cm) at 1.5cm/s, estimate the arc length of the path the observer sees.

3. The attempt at a solution

For a), the answer is obviously an arc. It would be ) if the disk is spinning clockwise correct?

As for b) I don't really understand. I can't seem to find the formula to be able to find the length of the arc. Since it definitely won't be in the shape of half of a circle, I can't use the formula for the circumference of a circle.. Any suggestions?

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Insect on spinning record problem

**Physics Forums | Science Articles, Homework Help, Discussion**