Bicycle Definition and 308 Threads

Hi! So I'm building an electromagnetic bicycle where the frame is levitating over the wheels, thus reducing the rolling friction to almost zero by removing the bearings. Magnets have also been placed alongside the wheels to provide side to side stability. Black is the frame, red are the magnets...

I'm planning to create my own bicycle in the university.It will have carbon fiber frame and as you know, there are some companies which can produce what you've designed in CAD software but I've no idea how much does it cost me to make them to produce a carbon fiber bicycle frame. Do you have...

Hello, I am curious if this has been done, or would even be worthwhile. The idea would be to use a generator at the pedal and conduct the electricity directly to a wheel motor with no power storage. This would eliminate gears and a chain. Does anyone know what the approximate efficiency of...

Hello, I need to know what is the best type of susension system for bicycles.And also rating of a motor to drive a 5 kg load.I am still studying B E .Please it is urgent. Thaks for helping.

[ mod note: thread moved to homework forum so template is missing ] Hello! My name is Marianne, and I'm a new member. This is my first post. (Yay!) I'm currently brainstorming ideas for the capstone/senior design project for engineering and decided airbags for bicycles... like a version of that...

Homework Statement Homework Equations pV = nRT The Attempt at a Solution I assumed that volume and temperature would stay constant. I assumed the volume wouldn't change because the volume of the tire doesn't change. This implies that n1/p1 = n2/p2 n1p2 / p1 = n2 I found n1 by using the...

You have 2 bikes. They only differ in 1 way. The length of the crank arm (where pedal attaches) https://en.wikipedia.org/wiki/Crankset How will these bikes differ when riding? Is one harder to pedal than the other? Why?

Hello, I made powerbank for my bicycle to charge my phone while I ride it. I am using one 4400 mah Li Ion battery. I was wandering If it is possible to charge the battery with less than 1 amp and not constant current? Because, generator I have on my bike produces 3W and it varies as I change...

Homework Statement [/B] A girl is heading home riding her bike she notices a giant wooden log is blocking the road 42m away. If the friction coefficient between her bike tires and the road is 0.36 and she is driving at 25km/h,then what is the distance required for her to stop given that the...

I started learning solidworks at my school and got this idea for a folding bicycle as I need one and they're really expensive. I was planning on modeling it after a montague paratrooper bike. Then I thought I could put an electric motor on the rear wheels either by a sprocket or by just...

I see that modern bicycles have curved front wheel forks , how does that affect stability ?

Interesting article on bicycle physics and researchers who've investigated it: http://www.scientificamerican.com/article/the-bicycle-problem-that-nearly-broke-mathematics/

Hello everyone :alien: I have been assigned to create a physics problem involving bicycles. I thought up the following, but I had questions regarding if it was properly made / worked out. A cyclist is accelerating constantly up a slope at 1 m/s ^-2 The slope is at a 15 degree angle and is 30 m...

How is in a bicycle puncture, the air flowing out of the puncture constitutes as an example for work done?

The CPSC has mandated every bicycle rim have a groove to indicate the wear on the rim. I have tested wheels extensively that I built over 100000 miles. As they wear from the brake pads the side walls will bulge from fatigue. If you are paying attention you can feel the brake grab at this spot...

So I'm just doing a project where i have a electrically assisted bicycle and I am struggling working out the power when the bike is going uphill. If i have a certain force provided by the rider, and a force provided by an electrical motor; can I do Power=F_{motor}* v_{motor}+F_{rider}*v_{rider}...

So when someone is simply cycling on a stationary bike, is that person doing any work? Because work is Force * distance. But there's no distance here, right? Is work simply the energy then?

John agreed to work after school for 8 weeks for a fixed weekly rate. But instead of being given only money for his work, John agreed to receive \$850.00 and a bicycle. After 5 weeks, John got sick. He was given \$250.00 and a bicycle. How much is the bicycle worth?

Homework Statement Consider a 18 speed bicycle, 3 gears are rotating with the pedal and 6 gears are rotating with rear wheel. Consider that the ones rotating with pedal, have radii 10 cm, 7 cm and 5 cm and the other ones have radii 3 cm, 4 cm, 5 cm, 6 cm, 7 cm and 8 cm. Calculate the torque on...

A bicycle wheel has a diameter of 73cm and is driven by a chain on a gear of 8.5cm diameter What is the ideal mechanical advantage? I know that IMA=de/dr But I'm not sure which one is de and which one is dr.

Hello! If I pedal a bicycle, where is the force that moves the bike forward horizontally applied? Is it the bottom of the back wheel or the center of the back wheel? When the force applied to that point is F, does all that force goes into horizontal acceleration, or does some of that force go...

Hello! The total force F = m*a applied to the bicycle is F = F1 - a*v^2, where F1 is the initial force applied to the bicycle, a is a constant and v is the velocity. That means that the total force applied to the bicycle decrease as velocity increases, like a wind resistance decreases...

Let's say you've got two electric bicycles both powered by identical 250W motors. Both are fixed gear. Both weigh about the same and have riders of the same weight. Both riders contribute no force to pedalling - all the work is done by the motors. The only difference is the first bike has 20"...

1. Homework Statement A guy is riding a bicycle, and we consider the front wheel, which has mass M, radius R and for the purpose of the moment of inertia can be thought of as a uniform disc. a) When the bike is going with linear speed v, what is the magnitude and direction of the angular...

Hey everyone, I am trying to figure out how to calculate how much total force is being applied to the wheel axle on a bicycle. I'm focusing on the rear wheel for the moment. For the sake of simplicity, let's say that the bike and rider together weigh 100kg and that 60 percent of that is going...

Hello everyone, I am currently trying to design some custom nuts for my bmx wheel axle but I have a few questions which I thought you guys might be able to help me with. First of all I've created an autodesk inventor model of the flange style nut I want to create but I'm not sure what material...

Hi there, I started working on an idea for an expandable gear CVT about 3 years ago, while out of work for a few months. I had some exciting progress on an idea that I think might be worth pursuing more, but I now have 2 kids, 2 jobs, and no time. I have brought up the project idea with a few...

We were asked a question about why there are spokes in a a bicycle wheel. Our teacher hinted that It was related to moment of inertia. Ok so this kind of a wheel will have a higher moment of inertia than say, a solid disk-like wheel. But how is that useful?

Hi everyone, I want to build a car-model which should be good enough to study under-steer/over-steer and test various safety algorithms like ABS, TCS, ESP. Initially I made a quarter car model, here I could implement simple ABS,TCS. Quarter car model supports only longitudinal dynamics and is...

Homework Statement Given: Wheel radius is 20 CM, Gear radius is 5 CM, Coefficient of Static Friction is .2, Weight on rear wheel is 50 N. What is the minimum force that must be applied to the pedal for the wheel to begin accelerating on a level surface?Homework Equations Net T = I * a T = R X...

Homework Statement Daniel Schroeder, introduction to thermal physics problem 1.36 (page 26): "In the course of pumping up a bicycle tire, a liter of air at atmospheric pressure is compressed adiabatically to a pressure of 7 atm. (Air is mostly diatomic nitrogen and oxygen.) a) What is the...

Hello! I have recently been looking into the phenomenon of gyroscopic precession in my free time, and there is a scenario which I am not sure I have fully understood. Here it is: Imagine a bicycle wheel with a shaft running through it's center. The shaft is attached to a rope at one of it's...

I'm wondering how the inventor of bicycle knew the fact that it would be possible to maintain balance on two wheels. Most kids fall off and bruise themselves in the beginning and there's no way of learning a bicycle other than trial and error. How did the inventor figure this out?

If I'll shove a bicycle down the road, without even being on it, it will go on perfectly without crashing, until it will reach to a minimal speed and then crash. Why is that? why can't we balance an imobile bicycle? A lot say it has to do with the gyroscopic effect but my physics professor said...

Hi, I have been tasked with finding a way to relate a bicycle tire's inflation pressure to its speed in traveling 160 meters. Data was given showing that as the pressure increased from 70 to 90 psi, the speed increased marginally. No equations were given. I think that it may have to do with...

I have been trying this problem for a while and can't seem to figure it out: A bicycle wheel has a radius R = 32.0 cm and a mass M = 1.82 kg which you may assume to be concentrated on the outside radius. A resistive force f = 137 N (due to the ground) is applied to the rim of the tire. A force...

I am trying to figure out the gear ratio's needed to turn a 24", 100 lb flywheel at 500 RM with a bicycle. I can not find a formula to calculate the size gears I will need. Can anyone point me in the right direction?

Homework Statement A wheel of a bicycle weighs 1 kg, all of which is at the rim. The diameter of the wheel is 0.7 m. If the bicycle is ridden at the speed of 3.5 m s–1, then in the frame of reference of the rider: i) Calculate the angular speed ω of the wheel. ii) Calculate the momentum of...

I wish to create a pneumatic bicycle but not sure if i should use high torque low rpm or higher rpm with lower torque. I am thinking that a low rpm with high torque will use less compressed air and make better use of the PSI.

Homework Statement A bicycle rider is moving with a velocity of 13.0 m/s. What is the angular velocity of his wheels if they have a diameter of 0.660m? Assume the wheels are rolling without slipping. a) 39.4 m/s b) 19.7 m/s c) 39.4 s-1 d) 4.29 s-1 e) none of the above Homework Equations v =...

Hi guys, This is the silliest thing. I actually solved problem and got the correct answer, but now I'm not sure that my logic was sound--or even what my logic really was! 1. Homework Statement While riding a multispeed bicycle, the rider can select the radius of the rear sprocket that is...

Hello! I'm hoping someone here can answer a question for me... I've observed that when pedaling a bicycle, if the rider moves from seated to standing position while maintaining the exact same cadence (pedal revolutions per minute) and resistance, power output (as measured on a power meter)...

I'm confused as to how gear ratios work in bicycles. I'm given a problem which says that gear ratio = rfront/rear. It then says that the gear ratio changes from 4 to 0.7. Does this mean that the radii of the gears are changing? I'm unfamiliar with gears on a bicycle so I'm not sure if the radius...

The locking mechanism of a bike skewer consists of a rod and slightly out of round disk on one side attached to the skewer. A handle is attached to the out of round disk as well Assuming the skewer is nearly snug with the wheel fork, I think the tension is going to be a function of the...

hi PF. i just want to ask if the formula P=Torque(angular velocity) is valid? saw this in wikipedia. if not, any idea how to measure the power exerted to a bicycle? thanks

Would it be possible to operate an electromagnet using the power produced by pedaling a bicycle? The electromagnet would need to be strong enough to lift up the training wheels of a bicycle.

Homework Statement A bicycle tire rotates at 30 radians/s. If the bicyclist travels at 10 m/s, what is the diameter of the tire? Homework Equations I found; for angular speed, w=v/r and for linear speed; v=rw where v=m/s and w=radians/s So if i am thinking correctly, i already know my angular...

Homework Statement Bicycle with a rider applying weight to on pedal. Draw as free bodies in equilibrium. There are different situations. Homework Equations N/A The Attempt at a Solution So I am working on part a). 1. I believe it is only referring to just the pedal, chain, and the two...

Hi, I'm a triathlete and a hobby constructor. I would like to build a power meter for my bike because the ones on the market are quiet expensive. The idea is to measure the power the rider puts into pedaling by measuring the tension between the pedal and the crank. They are connected with just...

http://www.newstatesman.com/science/2013/08/we-still-don%E2%80%99t-really-know-how-bicycles-work This is really kinda embarassing. Forget quantum mechanics our top scientists can't even figure out how a bicycle works. Is this true? I always figured it wasnt so much the gyroscopic effect of the...