illustrate which direction torque acts

Question

jamesj · Answer

The definition of torque is the vector cross product of the position vector r and the force vector F.
$$ \tau = r \times F $$
So if I am riding my bike, my action of pushing on the pedals makes the chain apply a force to the back wheel which makes it spin faster.  The $ \tau $ vector here points out to the side of bike, it is perpendicular to the plane in which the wheel is sitting.

This is not intuitive and takes some time to get used to.

aravindg · Answer

ya not getting it completely

aravindg · Answer

esp its direction

jamesj · Answer

watch the next MIT video on this topic.  He has several very compelling demonstrations will help you understand.  I can explain it formally here, but if you watch the demonstrations, you'll understand it better.

aravindg · Answer

do u have link?

jamesj · Answer

http://ocw.mit.edu/courses/physics/8-01-physics-i-classical-mechanics-fall-1999/video-lectures/ I think you've watched lecture 19. Now watch lectures 20 and 21. You won't get all of the mathematics he uses, but that's ok. You'll see the demonstrations and begin to get a feel for the topic. This is as I say, not intuitive.

aravindg · Answer

pls help with the other qns also

aravindg · Answer

i am gonna watch the video now

jamesj · Answer

I have already, haven't I?  What's not answered?

aravindg · Answer

look above