## sarah786 Group Title A cyclist cycling around a circular racing track skids because A.the centripetal force upon him is less than limiting friction B.the centripetal force upon him is greater then limiting friction C.the centripetal force upon him is equal to the limiting friction D.the friction between the tyres of the cycle and road vanishes 9 months ago 9 months ago

1. sarah786 Group Title

@AllTehMaffs :)

2. AllTehMaffs Group Title

Which one do you think?

3. AllTehMaffs Group Title

hai

4. AllTehMaffs Group Title

|dw:1382088401350:dw| Which way would the cyclist slide, and what are the two forces working against each other?

5. AllTehMaffs Group Title

:)

6. sarah786 Group Title

Centripetal and Centrifugal forces :/

7. sarah786 Group Title

is it B ?

8. AllTehMaffs Group Title

1/2 of that is right:) That half is 100 % right. Centripetal force pushing towards the center of the circle, and it's the friction that's applying the force. I drew the first diagram wrong. |dw:1382107001459:dw| The sum of all the forces is equal to the centripetal force $\sum F = F_f =m a_c = F_c$ I think I may have explained that poorly ;/ Centrifugal force doesn't really exist. The thing people call "centrifugal" force is just the tendency of your body to keep going straight while the car is turning. That's another question though :)

9. sarah786 Group Title

its B then ???

10. AllTehMaffs Group Title

Yup yup :) $a_c = \frac{v^2}{r}$ so if $F_c > F_f$ the bike skids.

11. sarah786 Group Title

ty so much :)