newton's law of motion in wheels?

Question

according to newton's law of motion, a body continues in its state of rest of uniform motion in STRAIGHT line unless disturbed by some external force. but a wheel of cycle rotates when the pedal is rotated but its motion is circular . where is STRAIGHT LINE motion. please clarify

Answer 1

Any circular motion is under an action of external force.

Therefore Newton's laws of motion is valid even in circular motion.

If the forces that cause circular motion are removed, then the motion will be in a straight line.

If a particle is moving in a straight line, it will move in a straight line until a force acts on it.

Suppose that a force acts perpendicular to its motion and that the force is always pointed toward a fixed point then the particle will move in a circular path.

Similarly a torque can produce rotational motion.

Torque is a force acting on a body in rotation at a distance from the axis of rotation. Torque will produce angular acceleration,

Coming again to bodies rotating with uniform angular speed,
one can always identify the centripetal force on EACH PARTICLE OF THE BODY UNDER ROTATION.

Thus a body is in circular motion only because of a force called centripetal force. Once that force is removed then each particle in the body will fly along a straight line as per Newton's laws of motion.

Answer 2

Maybe the pedal/chain/wheel system is abit too complicated right now.

Look only at the circles. The straight line motions are tangent to the circle. Instead of a bike wheel, imagine that you are twirling a rock on a string. When the string breaks (or you let go), the rock will fly off (initially) with straight-line motion (then gravity and air resistance get into the game making your life miserable).

Hopefully, you now see the origin of the centripetal or centrifugal force.

If you want to go back to the pedal bike system, the chain at the edge of the sprockets (gears) are moving in a straight line right before and right after they leave the (circular) gears. The teeth are just a mechanism to prevent slippage (another real world inconvenience ;-) ).

Answer 3

Multiple forces acting, one force acting against the point in rotation, pulling it toward the center of rotation; one force acting continuously on the point doing the moving, and the direction of that force is tangent to the point on the wheel at any given point in time, always changing therefor.

The context of yer question doesn't fit the question, it barely made sense readin it but that's what happens, would be easier to explain if I could draw in here damnit...

Answer 4

The force that is applied to the circular motion is in fact is stright. That's the answer. But the dircetion is circulate due to the acceleration side toward the centre.

Answer 5

any circular motion will lead to an external straight line motion( well it may not be straight line exactly but to some extent straight)
as you can see earth's self rotation will lead to a eliptical rotaion around sun this eliptical rotation may be due to sun's gravity othervise earth may experience a strighter path way than an orbit
in case of a cycle the straignt line has been utilised for forward movement .
this forward movement is wat newton talks about in his theory.

Answer 6

The exterior stress is the frictional stress which comes into the image whilst any 2 surfaces rub against each oyher(subsequently it will be the friction between the wheel and the ball bearings used to actual decrease the frictional stress). Hypothetically the wheel will shop rotating interior the absence of the frictional stress.