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. D

    Calculating Electric Motor Power for Bicycle Acceleration to 25 mph

    How do I go about calculating the required power of an electric motor (will be attached to bicycle) needed to accelerate a bicycle (about 200lbs) to a minimum of 25 mph? I'm not asking people to do all the work for me. I just want to know what I need to know in order to find the answer.
  2. T

    How Does a Bicycle's Friction Drive Work?

    Can anybody help me with these forces, I appreciate the effort. The roller shown sitting on top of the circle which is the bictcle tire is spinning counterclockwise imparting a tangential force on the bicycle wheel. Is the roller creating the force to drive the wheel forward, or is the entire...
  3. E

    Balancing a Bicycle: Why Hard When Not Moving?

    Hello, I am just thinking: why it is hard to balanca a (2-wheel) bicycle when it is not moving, while it is easy balanced when it is moving? I hope that I am asking in the right forum. Thanks in advance
  4. F

    What is the correct method for calculating the speed of a bicycle chain?

    Homework Statement A bicycle has wheels 67.3 cm in diameter and pedal cranks 17.5 cm long. The cyclist pedals at a steady angular rate of 71.5 rev/min. The chain engages with a front sprocket 15.2 cm in diameter and a rear sprocket 6.45 cm in diameter. Homework Equations v=rw The...
  5. P

    Maximum Tension in the Bicycle Chain

    Figure 1 below shows drawings of a typical bicycle chain. Consider two components of the chain: (i) the pin, and (ii) the link. The chain is under tension caused by a load applied by a person pushing on one of the pedals. Calculate the maximum tension in the chain. Calculate the stresses in...
  6. N

    Solving Stress in Bicycle Chain: A Guide for NDO

    Homework Statement See attachment for the problem. or visit the link http://i908.photobucket.com/albums/ac286/NDO_02/Capture.jpg Basically calculate the stress in the pin and the link in a bicycle chain. Homework Equations the average shearing stress = P/A = F/A i think the chain...
  7. A

    Creating a Bicycle-Powered Woodcutter for Logs: Suggestions Needed

    I and few of my pals are making a project. A circular blade woodcutter saw powered by bicycle pedalling for cost effective design for rural people where electricity is a problem... We plan to cut Logs with it...and their cross section can be random... Using a big circular blade. Now...
  8. J

    Solving Bicycle Brake Problem: Acceleration & Time to Stop

    Homework Statement A person is riding a bicycle at a constant speed v along a straight road and then gradually applies the brakes until the bicycle comes to a stop. Assume that the magnitude of the braking force increases liearly in time acordinto F = bt where b is a constant. The rider &...
  9. R

    Automatic gear changing bicycle

    hi.. i want to make a automatic gear changing bicycle in which instead of manual changing of gears they change automatically with variation of speed... for this project i need help..if you know any thing about this then please reply...by posting
  10. N

    Calculating Angle of Wheel Rotation for Rolling Bicycle

    Homework Statement A bicycle is rolling down a circular hill that has a radius of 9.00m. The angular displacement of the bike is 0.960rad. The radius of each wheel is 0.400m. What is the angle (in radians) through which each tyre rotates ? Notes on question : - wheels are in rolling...
  11. W

    How to: compute Watts and Calories for for a bicycle, up a hill

    At 6'5", 300 lbs. and old as dirt, I am a walking and rolling testimate to F=ma. This part of my project is difficult for me, because I have never taken a physics class. All the examples I have in books and PF, deal mostly with force moving down a hill. I am trying to compute Watts and Calories...
  12. W

    Need help with my bicycle computer project

    I am trying to work out the physics used in a micro-controller project. I am having problems with even simple relationships, like F = ma. My answers end up with much larger numbers than, a man on a bicycle should be capable of. This is just a hobby for me, and I haven't taken a physics class...
  13. F

    Triggering a trafic light on a bicycle.

    i'm a cyclist. Some traffic lights aren't triggered by bicycles. What is the frequency of the AC signal in the coils imbedded in the road to detect cars? Could I build an RLC circuit about the size of my foot that would trigger the light? Knowing the actual frequency is critical to choosing...
  14. F

    Explaining Bicycle Gear Ratios to Non-Physicists

    I am a cyclist and am starting to think about gear ratios. I have counted teeth on my bike gears (touring) and calculated ratios and the results do not make sense to me. I am left with the beliefe that ratio is not all at work here. It seems that it also has to do with the diameter of the gear...
  15. T

    What is the average velocity for a bicycle's trip?

    Homework Statement A bicycle travels 3.2 km due east in 0.10 h, then 4.7 km at 15.0° east of north in 0.14 h, and finally another 3.2 km due east in 0.10 h to reach its destination. The time lost in turning is negligible. What is the average velocity for the entire trip? I need to find the...
  16. K

    Low Rider Bicycle Steering: What's the Lowest Angle?

    just like the title says at what angle can you put the front wheel of a bicycle in relation to the ground and still be able to steer it with moderate percision now when i say angle i mean like a low rider you know the bicycles that have the really long front fork and look cool so basically my...
  17. H

    Bicycle Rear Shock damping coefficent

    Just carrying out calculations on a rear bicycle shock. Got my hands on one and intended to calculate spring stiffness and damping coefficent practically. Did it on the spring using a tensile tester and have come up with a spring stiffness value of 130000 n/m2. (750 lb/in). Problem when i...
  18. P

    Free-body Diagrams for Bicycle and Person sitting on it

    A person is on a bicycle, there are several situations like the bike is at rest, accelerating,etc. The one I'm having most trouble with is when bike is in constant velocity. For the bike,I have gravity and force of person acting downward, normal force upward, force applied to the right and...
  19. H

    History Is Bicycle Suspension Really Necessary?

    Hey Guys, I'm doing a research project on the bicycle suspension. I would like to include a brief history of the suspension in my report. I am having trouble finding when bicycle suspension was first introduced, and what sort of systems were originally used, who patented it etc. Any help or...
  20. H

    Weight Distribution on a Bicycle: How Does It Affect Suspension Response?

    Hey guys, I'm currently doing a project on bicycle suspension response. My query is how is a cyclists weight distributed over the two wheels of the bike. I realize it is going to change depending on the position of the cyclist. I'm just concerned with a "normal" recreational position. I am...
  21. D

    What are the principles involved in this bicycle scenario?

    What are the formal principles of math and physics that describe this scenario? Most local laws require bicyclists to ride with (i.e. in the same direction as) traffic. The rationale behind this is that as a car and a bike are traveling in the same direction the car has more time to react to...
  22. F

    Is a bicycle or dirtbike an example of f=ma?

    Hey all - this is my first post so I mght as well say hi - I'm not very smart, but find everyday physics interesting. I tried to look up Newton's Laws, but I can't figure out: Is a dirt bike or bicycle a good example of the f=ma principle? All the info I found states that the force is...
  23. T

    Faraday's law + bicycle training

    Can anyone verify that I'm thinking about this situation correctly: among cyclists, there exists a thing called a roller trainer, which allows cyclists (or anyone who wants a workout) to train indoors (eg when it's too cold out). It looks like this...
  24. T

    Well-lubricated bicycle wheel problem

    Homework Statement A well-lubricated bicycle wheel spins a long time before stopping. Suppose a wheel initially rotating at 170 rpm takes 70 s to stop. A)If the angular acceleration is constant, how many revolutions does the wheel make while stopping? Homework Equations i used...
  25. C

    Is Energy Required to Ride a Bicycle the Same for Every Rider?

    This is my first and probably only question on here. Is it true that the same amount of energy is required to pedal a bicycle from point A to B, no matter the condition of the rider, or the gear ratios used, or the time it takes, as long as every thing else is equal? Weight, rolling...
  26. P

    A bicycle tire that has a slow leak,

    Homework Statement If you poke a hole in a container full of gas, the gas will start leaking out. In this problem you will make a rough estimate of the rate at which gas escapes through a hole. Your bicycle tire has a slow leak, so that it goes flat within about an hour after being inflate...
  27. G

    Calculate Torque to Move Bicycle - 490N of Friction

    The following attached file is a free body diagram for a bicycle. Please excuse the crudity of the drawing, I drew it on paint. The bicycle weighs 100 kilograms with the rider on it and has 26 inch wheels. The bicycle is at rest. The static coefficient of friction between the wheels and the road...
  28. F

    What is the Maximum Acceleration for Contact of Skidding Bicycle Tires?

    Homework Statement A simplified model of a bicycle of mass M has two tires that each comes into contact with the ground at a point. The wheelbase of this bicycle (the distance between the points of contact with the ground) is w, and the center of mass of the bicycle is located midway between...
  29. M

    Bicycle gears, energy, work and power?

    Bicycle gears, energy, work and power?? hi everyone, let's say you're riding a bicycle, and as you approach a hill, you shift to a lower gear. You pedal at the same rate, however. Does the power increase, decrease or stay the same? An explanation would be helpful. I've been trying to reason...
  30. O

    Time in min. it takes Jessica to bicycle to school

    Homework Statement The time in minutes (min.) it takes Jessica to bicycle to school is normally distributed with mean 15 and variance 4. Jessica has to be at school at 8:00 am. What time shoud she leave her house so she will be late only 4% of the time? A. 8:00 B) 11.5 min. before 8:00 C)...
  31. A

    Motorcycle vs Bicycle chain tension

    Trek recently released a belt driven bicycle (instead of chain drive) which led to a discussion among some cycling friends. Which led to discussion of torque, power output, etc. Anyway, I'm trying to compare the chain tension of a motorcycle vs the chain tension of a bicycle. I'm better with...
  32. K

    The difference between rear and front brakes of a bicycle

    Hi, I'm a sophomore student at Arizona State University studying Aerospace. I'm currently taking my first physics class ever and I'm loving it. Although there isn't enough calculus, it's mostly formula based, so it's a bit disappointing on that end. Anyways, ever since I started taking the...
  33. B

    Linear acceleration of bicycle

    Homework Statement A bicycle has wheels with a radius of 0.295 m. It accelerates uniformly and the rate of rotation of its wheels increases form 209 rpm to 265 rpm in a time of 20.7 s. What is the linear acceleration of the bicycle? ω=angular vel. α=angular accel. Homework Equations...
  34. L

    Improve Bicycle Braking System with Momentum Research - Luke Mace

    hello to everyone this is my first post on this website but have used it before and found existing posts and answers very helpfull. i am a engineer at bourneouth university studying BSc Computer aided product design, i am currently working on research into a bicycle braking system to improve the...
  35. fluidistic

    Rotating bicycle wheel question

    Hey, Today I assisted to a lecture I didn't understand in Physics I. I've asked to a helper-teacher a question and he made me much more confused. Say I have a rotating bicycle wheel in my hands (my hands don't influence the wheel's rotation) in front of me such that the wheel is in a...
  36. Y

    Bicycle Shock Absorber Question

    I have a mountain bicycle with a rear spring shock absorber. Recently the shock absorber broke. Until I can purcahse a replacement I was thinking of building a rigid piece of steel to replace the shock, essentially making my bike a non-suspended unit, but still be able to ride it. So here...
  37. M

    Angular Acceleration of a bicycle

    A bicycle has wheels of 0.8 m diameter. The bicyclist accelerates from rest with constant acceleration to 22 km/h in 13.7 s. What is the angular acceleration of the wheels? relevant equations: omega = omega initial + alpha * t 22km/h = 6.11m/s I did 6.11m/s * 13.7s = 83.7207 to get the...
  38. S

    Exploring the Relationship Between Bicycle Pedals and Sinusoidal Force

    Hi, I'm new to the forum so I hope this is the right place to post this, I actually joined to ask this question. I found something in the archive through a google search. The thread can be found at: https://www.physicsforums.com/archive/index.php/t-117265.html Some of the things in there were...
  39. M

    Electric bicycle that can re-charge itself?

    (Complete physics novice here - I know very little about physics, so please excuse any stupid questions!) I was reading the 'Electromagnet' thread, about how movement (preferably rotation) is best for generating power using magnets... What I'm wondering, could you use the rotation of the...
  40. Y

    Calculating Temperature Rise of Air in Bicycle Pump

    Homework Statement A bicycle pump is a cylinder 20cm long and 3.0cm in diameter. The pump contains air at 21.0C and 1.0atm. If the outlet at the base of the pump is blocked and the handle is pushed in very quickly, compressing the air to half its original volume, how hot does the air in...
  41. J

    Solving a Bicycle Physics Problem: Finding Position, Velocity, and Acceleration

    Ok so I have this physics problem but for some reason I feel like its a typo or I am missing some informtion, here is the problem A bicycle os moving east beginning at a position of X1=2.0m at T1=0.0s. At the time T2=2.0s find the bicycle's A) position, X2 B) velocity, V2 C) acceleration...
  42. 4

    Exploring Work and Power Output Differences in Cyclists on the Same Hill

    Homework Statement If 2 bicyclists are cycling to the top of the same hill, and one bicyclist is using a gear that is twice as difficult as the other, is there a difference in work and power output between the 2 cyclists?
  43. W

    What size tires and tubes should I get for my hybrid bike?

    After riding to work a lot during my internship/REU/whatever thing, I'm back home and want to keep riding anywhere I can. I have an old hybrid mountain/road bike which I really like, but the tires are getting old, especially the back one is getting frayed and I'm getting a bumpy ride for some...
  44. Y

    Understanding the Physics Behind Bicycle Helmet Design and Use

    I am doing a lesson on Energy and Momentum and I am asked to write a report that includes sample calculations and examples, a thorough discussion of the principles of physics pertaining to energy and momentum, and apropriate diagrams and notations to demonstrate my understanding between the...
  45. Ed Aboud

    Easier to balance on a bicycle when you are cycling faster

    Why is it easier to balance on a bicycle when you are cycling faster rather than slow? Does it have something to do with angular momentum? Thanks.
  46. J

    Modify Bike to Generate Electricity: Electric Bicycle

    im pretty sure a bunch of people have done this before. I am wondering if i could modify my own gear bike so that as the wheels spin, they generate electricity and is collected into a battery. then i can turn on a light-weight electric motor so the wheels will either spin on their own or just...
  47. C

    Kinetic energy bicycle problem

    Homework Statement How much work is done by an Olympic triathlete who accelerates herself on her bicycle (combined mass of 105kg) from 5 m/s to 10 m/s? Homework Equations Ek = 1/2mv^2 W = Fapp(d) The Attempt at a Solution Ek = 1/2m[(5 + 10)/2]^2 how do i go about solving this?
  48. N

    How Do You Calculate the Final Angular Speed of a Bicycle Wheel?

    [SOLVED] Angular Speed \tau = r * F Homework Statement youve got our bicycle upside-down for repairs with its 66 cm diameter wheel spinning freely at 230 rpm. the mass of the wheel is 1.9 kg and is concentrated mostly at the rim. you hold a wrench against the tire for 3.1s with a normal...
  49. R

    Rotational Kinetic Energy of bicycle wheels

    A bicycle has wheels of radius 0.33 m. Each wheel has a rotational inertia of 0.082 kg* m2 about its axle. The total mass of the bicycle including the wheels and the rider is 74 kg. When coasting at constant speed, what fraction of the total kinetic energy of the bicycle (including rider) is the...
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