Factors affecting friction
The intensity of friction depends on following factors: i) The area involved in friction. ii) The pressure applied on the surfaces. Force = Pressure ´ Area Frictional force will increase, if the area of contact will increase or if pressure applied on the surface increased.
Methods to reduce friction
i) Polish the contact surface. ii) Put oil or grease so that it fills in the small gaps of the flat parts. iii) Use ball bearings to reduce area of contact between rotating parts.
Lubrication
Following methods can be used to reduce friction: Oil is either thin or viscous. It depends upon SAE No. of oil. (SAE means Society of Automotive Engineers). If we use very viscous oil, it does not reach all the parts. Very thin oil will flows away easily and gets wasted. Grease is used in such cases. It is generally used around ball-bearing. Normal grease or oil is never used where there is high pressure, high temperature and high speed. Special lubricants are used in such cases. In cold season the oil becomes thick and in hot season it becomes thin. Therefore selection of lubrication also depends on the season. It is always advisable to refer operating manual of the equipment before selecting the lubricant.
Answer:
speed will double
Explanation:
Tangential velocity is given by
v=wr
where r is radius and w is rotational velocity. When r is increased to 2R, keeping roational velocity constant, the tangential velocity doubles. Hence unwinding will take place at a twice the rate and the final velocity will be double
22.3 rad/s
<h3>
Further explanation</h3>
We will solve the question of uniform circular motion.
<u>Given:</u>
- A bicycle has tires of radius
- The bicycle is traveling at a constant speed of

<u>Question:</u>
What angular speed are the tires rotating?
<u>The Process:</u>
Speed, angular speed, and radius are connected in the following formula:

The angular speed is worked out by

All units are in the SI system so let us calculate the angular speed.

Thus the value of the angular velocity of the rotating tire is 
<u>An additional question:</u>
What is the frequency of tire rotation?
Recall this formula: 

We get 
<h3>Learn more</h3>
- Arc CD is ²/₃ of the circumference of a circle. What is the radian measure of the central angle? brainly.com/question/2115496
- A triangle is rotated 90° about the origin brainly.com/question/2992432
- Particle's speed and direction of motion brainly.com/question/2814900
Keywords: a bicycle has tires of radius 0.35 meters. traveling, at a constant speed of 7.8 m/s, at approximately, angular speed, the tires rotating