What is Bicycle: Definition and 319 Discussions

A bicycle, also called a bike or cycle, is a human-powered or motor-powered, pedal-driven, single-track vehicle, having two wheels attached to a frame, one behind the other. A bicycle rider is called a cyclist, or bicyclist.
Bicycles were introduced in the 19th century in Europe, and by the early 21st century, more than 1 billion were in existence. These numbers far exceed the number of cars, both in total and ranked by the number of individual models produced. They are the principal means of transportation in many regions. They also provide a popular form of recreation, and have been adapted for use as children's toys, general fitness, military and police applications, courier services, bicycle racing, and bicycle stunts.
The basic shape and configuration of a typical upright or "safety bicycle", has changed little since the first chain-driven model was developed around 1885. However, many details have been improved, especially since the advent of modern materials and computer-aided design. These have allowed for a proliferation of specialized designs for many types of cycling.
The bicycle's invention has had an enormous effect on society, both in terms of culture and of advancing modern industrial methods. Several components that eventually played a key role in the development of the automobile were initially invented for use in the bicycle, including ball bearings, pneumatic tires, chain-driven sprockets and tension-spoked wheels.Although bike and cycle are used interchangeably to refer mostly to two types of two-wheelers the terms still vary across the world. In India for example a cycle refers only to a two-wheeler using pedal power whereas the term bike is used to describe a two-wheeler using internal combustion engine or electric motors as a source of motive power instead of motorcycle/motorbike.

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  1. T

    Rotational Kinematics of bicycle breaks

    [SOLVED] Rotational Kinematics Homework Statement A person is riding a bicycle, and its wheels have an angular velocity of +18.0 rad/s. Then, the brakes are applied and the bike is brought to a uniform stop. During braking, the angular displacement of each wheel is +13.5 revolutions. (a)...
  2. V

    Variable diameter bicycle wheel

    I'm attempting to write a simple model to describe the angular velocity profile (aka angular acceleration) of a bicycle wheel for different torque vs time profiles. Where this gets complex is that it's not a normal bicycle wheel. It is a normal wheel with weights on the spokes connected to...
  3. M

    Friction bicycle homework Problem

    [SOLVED] Friction Problem Homework Statement A bicyclist can coast down a 5° hill at a constant 8.0 km/h. Assume the force of friction (air resistance) is proportional to the speed v so that Ffr = cv. (a) Calculate the value of the constant c. ________ kg/s (b) What is the...
  4. S

    Building a Bicycle with a Flywheel | Chris

    Hi all, whilst bored recently I thought wouldn't it be a great idea to have bicycles where the pedals accelerate a massive flywheel and then you release some kind of clutch mechanism to propel the bike forwards. As i thought about it the main problem was what to use for such a flywheel (I was...
  5. S

    Bicycle physics - Flying over the handlebars

    It is known that maximum braking occurs when the front brake is applied so hard that the rear wheel is just about to lift off. Skilled cyclists use the front brake alone probably 95% of the time. However, improperly modulating the force applied on the front brake will bring the bike to a...
  6. O

    Solving Bicycle Problem: Will it Move Forward or Backward?

    [SOLVED] Bicycle problem Will the bicycle move forward or backward? We have 2 forces. The friction and the one we act on the wheel through the string. The weight and the normal force have torque equal to zero. torque of the friction = T.r1 torque of the F = F.r2 In the second picture r1>r2...
  7. K

    Question: stability of bicycle

    Hello, I'm doing a big physics lab for my extended essay (IB diploma). I'm exploring two things, where my question is what affects the stability of a bicycle more, velocity or the weight on the bicycle? So for the first variable velocity, i pushed the bicycle in different strengths to alter...
  8. P

    Forces Applied to Bicycle Pedals

    Hi, I’m not an academic and I would like clarification on the following questions. I have searched your forum and the web in general for the answer in order to avoid unnecessarily bothering anyone but was unable to find the answer. Here are my questions. Barring minor influences of...
  9. S

    What is the bicycle speed after the throw?

    Homework Statement Tony of mass 55kg coasts on his bi cycle of mass 5 kg at a constant speed of 5m/s carrying a 6kg pack. tony throws his pack forward, in the direction of his motion, at 1 m/s relative to the speed of bicycle just before the throw. Initial momentum of system (tony...
  10. J

    Angular velocity and bicycle wheel

    I am a little stuck with angular velocity and I do not know where to start on this one question. A bicycle wheel has a diameter 60 cm. Determine its angular velocity in radians per seconds, when the bicycle travels at 20km/h Could somebody please help as to where to start Very much...
  11. J

    Calculating Pressure of Air After a Bicycle Pump Stroke

    A bicycle pump contains air at STP. As the tire is pumped up, the volume of air decreases by 30% with each stroke. What is the new pressure of air (in atm) in the chamber after the first stroke, assuming no temperature change? Select the correct answer. a. 1.4 b. 0.7 c. 2.6 d. 0.9 e. 2 What...
  12. R

    Riding a Bicycle: What Will Happen?

    Homework Statement A boy is riding a bicycle on a straight, level and smooth road. There is no wind. He accelerates to 15m/s, and then suddenly stops pedaling. What will happen? a) immediately begins to slow because of inertia b) slows because of inertia, but not immediately c) slows...
  13. A

    How do gyroscopic forces affect a bicycle's stability?

    My dad gave me this riddle eight months ago, can anyone help? Why doesn't a bicycle fall over when its moving. P.S its not balance , as you can push it and it won't fall over for a while.
  14. S

    Medical Is it healthy to bicycle ALL THE TIME?

    Since, the only reason we get tired and muscles wear out is b/c of lack of oxygen...if I drive the bicycle machine really slowly, and do all my word on it...(use it as a desk) Is that a bad idea?
  15. A

    Building a Bicycle with Mechanical Regenerative Braking

    I am planning to build a bicycle with mechanical regenerative braking. I am thinking of setting a spiral spring to wind during braking and use its tension to assist in climbing hills Would such a spring give me enough power for this? Are there any other alternatives? Is this feasible?? Any...
  16. K

    What is the Precession Frequency of a Rotating Bicycle Wheel?

    Homework Statement A professor holds a bicycle wheel rotating at 402 rev/min by a string attached to a weightless axle 20 cm from the wheel. The acceleration of gravity is 9.8 m/s^2. If all 7.5 kg of the wheel can be considered to be at its 53.6 cm radius, at what frequency in rpm does it...
  17. F

    How do different variables affect the power needed to ride a bike?

    Dear Gurus, I'm coding a microprocessor controller for a 0.1hp motor. to assist going up hill on a bike. But the RR equation seems strange I found the equations relating the bike losses, mechanical, rolling resistance , airdrag... with speed and hence horsepower and calories. Here...
  18. H

    How useful is a bicycle as a form of transportation to you?

    In the "Nobel winning physicist takes on Global Warming' thread there were a few posts about bicycle use that I found interesting. I realized that I could use a bicycle rather than an automobile for about 90% of all my travel needs. Living in Portland, the public transportation system is...
  19. E

    Does a Spinning Bicycle Wheel Conserve Kinetic Energy and Momentum?

    2 questions. 1.when you're spinning wheel by its shaft, does the wheel have any kinetic energy while it's spinning?is it conserved?explain why. 2.does the wheel have any net momentum while it's spinning? is it conserved?explain why
  20. D

    How to calc human bicycle power in watts

    Homework Statement How to calculate Lance Armstrongs power output/calorie consumption at 30 mph, 125 miles on level ground , no wind, 157 lbs plus 16lb bike? Homework EquationsWhat equations do I use? The Attempt at a Solution I'm 14 years old, where do I start
  21. F

    Bicycle Problem Homework: Find Power for 85kg Man on 5.2° Incline

    Homework Statement What power must a man of mass 85kg have to bicycle 850m up a hill, inclined at 5.2 degrees to the horizontal, at a constant speed of 15.6 m/s? The force of friction on the man and the bicycle is 175N parallel to the incline. Homework Equations Fnet=ma W=delta E The...
  22. J

    Fixing Bicycle Frame: Troubleshooting Loose Parts and Handlebars

    i got a new frame for my bike an attempted to swap all the parts (pretty brave i know). when i went to put the parts back the way they were not all fitted. i removed the forks and the handle bars, and now when coming to put them back, the long pin with the hex allen key part will not tighten up...
  23. P

    Raising a Bicycle Wheel: Minimizing Force Required to Overcome a Curb

    Homework Statement You are trying to raise a bicycle wheel of mass m and radius R up over a curb of height h. To do this, you apply a horizontal force F. What is the least magnitude of the force F_vec that will succeed in raising the wheel onto the curb when the force is applied at the center...
  24. F

    Linear Acceleration of a Bicycle with Changing Wheel Rotation

    Homework Statement A bicycle has wheels with a diameter of .600 m. It accelerates uniformly and the rate of rotation of its wheels increases from 215rpm to 275rpm in a time of 24.3 seconds. Find the linear acceleration of bicycle. Homework Equations w =wi + alpha(time) The Attempt...
  25. A

    Double Checking a Bicycle Downhill Homework Problem

    Homework Statement I wasn't sure if i was doing this problem correctly, if anyone could double check for me, that would be great! You ride your bicycle down a hill. Your total mass is 40 kg. At the top of the hill, your speed is 5 m/s. The hill is 20 m high and 200 m long. If the force of...
  26. A

    Calculating Speed of Bicycle on a Hill | Mass, Height, and Distance Given

    Homework Statement You ride your bicycle down a hill. Your total mass is 54 kg. At the top of the hill, your speed is 5 m/s. The hill is 1 m high and 101 m long. what is your speed at the bottom of the hill? Homework Equations The Attempt at a Solution PE= mgh (54)(9.8)(10)...
  27. P

    How much work is done on a bicyclist and her bike when coasting up a hill?

    Homework Statement Coasting along at 7.10 m/s, a 60.0 kg bicyclist on a 7.60 kg bicycle encounters a small hill. If the speed of the bicyclist is 6.00 m/s at the top of the hill, how much work was done on the bicyclist and her bike? Homework Equations KEf-KEi=W .5mvi^2-.5mvf^2...
  28. B

    Why Do Tension Measurements Differ in Bicycle Incline Experiments?

    Homework Statement About a year ago I prepared a test for a bicycle on an inclined plane by: tying down the handlebars, so they wouldn't move much removing the chain and tying a wire to a tension scale and the bicycle in 2 ways. 1. I attached a wire to the rear wheel and the scale, and...
  29. B

    How Does Tension Affect a Bicycle on an Incline?

    Homework Statement A 14kg bicycle is on a 12 degree incline. A tension scale is connected by a rope to both the rear wheel circumference and a metal bar that is extending the bicycle frame rearward. The line of the rope is at a 30 degree angle to the metal bar. What will be the reading on...
  30. B

    Bicycle and Pulley: What Will the Scale Read in Two Different Examples?

    Homework Statement What will the scale read in these 2 examples? The incline is 12 degrees. The bicycle weight is 14kg. The cylinder weight is 14kg. Homework Equations Force of 2nd pulley 'arm' is 1/2 weight Force on incline is force X sin(angle) The Attempt at a...
  31. F

    Calculating Horizontal Force of a Bicycle Tire

    Homework Statement A bicycle has 30cm radius tires with gear and pedal dimensions as shown. IF the maximum vertical force that a 70kg rider can exert is equal to his/her body weight, what is the horizontal force that can be exerted on the ground by the rear tire...
  32. Ivan Seeking

    Pacific Wind's ThrustPac: Bicycle Jet Backpack

    Bicycle "Jet" Backpack http://www.netscape.com/viewstory/2006/10/04/propeller-propulsion-to-use-with-your-bicycle/?url=http%3A%2F%2Fwww.kirou.com%2F2006%2F10%2F04%2Fpersonal-jet-pack%2F&frame=true Pacific Wind homepage http://www.personalpropulsion.com/products.htm
  33. K

    Bicycle Wheel Friction: Average Torque Calculation

    A bicycle wheel, of radius 0.330 m and mass 2.00 kg (concentrated on the rim), is rotating at 4.12 rev/s. After 48.0 s the wheel comes to a stop because of friction. What is the magnitude of the average torque due to frictional forces? First I did I = (1/2)(mr^2) = (1/2)(2kg)(0.330^2 m) =...
  34. F

    Calculating Power Output to Climb a 7.0 Degree Hill

    A bicyclist coasts down a 7.0 degree hill at a steady speed of 5.0 m/s. Assuming a total mass of 75kg (bicycle plus rider), what must be the cyclist's power output to climb the same hill at the same speed? I get 90N * 5.0 m/s = 450W The book says 9.0 * 10^2 W It looks like I'm...
  35. K

    Rolling Friction and Bicycle Tires, Mastering physics problem.

    Information given: Two bicycle tires are set rolling with the same initial speed of 3.60 m/s along a long, straight road, and the distance each travels before its speed is reduced by half is measured. One tire is inflated to a pressure of 40 {\rm psi} and goes a distance of 18.1 m; the other...
  36. V

    How much energy does a bicycle diname produces?

    So my question is actually really simple.I want to know approximately how much energy does a normal dynamo produce when a bicycle wheel is spinning (at let's say 10 km/h).Please answer me with a number not with a formula because I'm really bad at physics but i just want to test a theory of mine...
  37. J

    Moment / CG question regarding a bicycle

    Hi, Lets say that we have a 2 wheel bicycle riding at 2m/s. The weight distribution on this bicycle implies that the front wheel is exerting a total of 400N on the ground, whilst the back is exerting 560N. How would I work out whether at this speed if I were to lock up the front brake...
  38. Math Is Hard

    I need a light, collapsible bicycle

    I remember years ago seeing a bicycle that was very light and collapsible. You could even carry it. It was tremendously expensive, though. Do they still make such a thing? It would be very helpful in getting around campus. I need to be able to fit it into my car so I could transport it from...
  39. daniel_i_l

    Bigger Wheels Roll Down Hill Faster: The Reason?

    I noticed that if two bicycles roll down a hill, then the one with bigger wheels will get to the bottom first (I tested this with my brother). I could only think of one explanation: The bigger wheels make less revolutions and thus have less friction. Is that the reason? Are there other ones...
  40. B

    Bicycle design and materials tehnology

    Any good sites/other resources that I could look at?
  41. S

    Speed of a bicycle - circles

    Suppose you ride a bicycle on a horizontal surface in a circle with a radius of 20 m. The resultant force exerted by the road on the bicycle (normal force plus frictional force) makes an angle of 15 degs with the vertical. a. What is your speed? b. If the frictional force is half its maximum...
  42. P

    Rolling Friction and Bicycle Tires

    my teacher Never went over this in class. ever. please help, thanks Two bicycle tires are set rolling with the same initial speed of 3.70 m/s along a long, straight road, and the distance each travels before its speed is reduced by half is measured. One tire is inflated to a pressure of 40 psi...
  43. W

    How do people maintain balance while riding a bicycle or skating?

    Hi, I have a question: How does people keep balance when they riding a bicycle or skating? Moving seems to be essential, when riding a bicycle, we can argue that the wheel is rotating, so it's angular momentum keeps the balance. But in the case of skate, nothing is rotating, but people seem to...
  44. R

    Pennytech Bicycle rack for a motorcycle

    "Pennytech" Bicycle rack for a motorcycle i quess this can be the second part of a "Theme" of posting to present my little works of passion... first I'm sure many of you are going to think and express this is to dangerours,, well i have about 150,000 milles of riding using it without any...
  45. B

    The Mystery of the Upright Bicycle: Exploring Balance

    This question has been bothering me for time. How does a moving bicycle manage to stay upright? but when it slows down it tends to fall to a side. Can someone please explain?
  46. siddharth

    The Mystery of Bicycle Wheel Sizes: Stability or Ease of Use?

    Why are Bicycle wheels the same size? Is it because it is easier to manufacture and maintain or does having same wheel sizes in the front and back offer added stability when compared to having a bigger wheel at the back (like the early models)?
  47. L

    F = Minimum Force Required to Lift Bicycle Wheel off Ground

    The figure shows a bicycle wheel resting against a small step whose height is h = 0.110 m. The weight and radius of the wheel are W = 29.0 N and r = 0.350 m. A horizontal force F is applied to the axle of the wheel. As the magnitude of F increases, there comes a time when the wheel just begins...
  48. L

    What Force Lifts a Bicycle Wheel Over a Step?

    The figure shows a bicycle wheel resting against a small step whose height is h = 0.110 m. The weight and radius of the wheel are W = 29.0 N and r = 0.350 m. A horizontal force F is applied to the axle of the wheel. As the magnitude of F increases, there comes a time when the wheel just begins...
  49. A

    Explaining Forces in Bicycle Riding: How to Help Your Little Brother

    Hi guys, my teacher gave every person in my class a problem to think about over the weekend...it should be pretty easy but let's just say that physics isn't my subject hahaha. well i was hoping you guys could help me out with this, the problem says: "You are teaching your little brother to...
  50. wolram

    Finding the Right Bicycle for Longer Rides

    I am thinking if buying one for next summer, but my memories of having on when i was a kid are not good, cycling any distance left me with a sore bum, i have looked at some of the modern bicycles and they seem a bit bare, no mud guards and very little chain guards, the ones i looked had...
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