Bike Definition and 189 Threads

Hello, while my question is not from a textbook, it still has to do with a lab I'm creating. My lab was to view the efficiency of rotational KE of a bike's pedals to the KE of the bike itself. Using 1/2*I*ω^2 and 1/2*m*v^2 to find KE, I seemed to have run into a problem. The KE of the bike was...

Hello there, This is my first post on here, so I hope that I've posted in the appropriate sub-forum. My question might seem simple to some, but I haven't been able to find a satisfactory / understandable answer to this question. Thanks in advance for taking the time to respond.

Why is it that it's much easier to balance on a moving bike than a stationary one? I've heard a few different answers: 1. The wheels of the bike each have their own angular momentum vectors, which like to stay pointed in the same direction, and hence resist tipping from side to side (sort of...

Homework Statement Two bicycle tires are set rolling with the same initial speed of 3.60m/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 and goes a distance of 18.0m ; the other is at...

Dear Friends I’m in need to solve a problem in physics, which might be easy for you but it is not for me as my background in physics is not good. I have a bike (drawn in simulation platform) with a flywheel connected to the crank (or shaft). The flywheel is not always fixed (or engaged)...

Homework Statement A truck is stopped at a traffic light. The moment the light turns green, it begins to accelerate constantly at 3.1m/s^2. A cyclist approaching the truck from behind with a constant velocity of 10m/s was 7.5m behind the truck when the lights turned green. 1)How much time...

Homework Statement Vroom, vroom! As soon as a traffic light turns green, a car speeds up from rest to 50.0 mi/h with constant acceleration 9.00 mi/h + s. In the adjoining bike lane, a cyclist speeds up from rest to 20.0 mi/h with constant acceleration 13.0 mi/h + s. Each vehicle maintains...

Homework Statement A bike is going clockwise around a circle of radius R (see below). The moment of inertia of each wheel around its center I_cm is NOT negligible. What is the direction of the total Angular Momentum of the bike about the center of the circle (point Q)? Consider when the bike...

Hi! I simply wonder how it is possible to ride a bike. I do not understand why the pure forward motion cancels the mass-centre offset which I think always should be inherent in riding a bike. With mass-centre offset I mean that looking at the rider vertically it is impossible to keep...

Hi all, new on here so thanks in advance for your responce's I am an avid cyclist and competant engineer, i dislike oil and gas so much i do not own a car. I cycle everywhere. I am tired of wanting to go long distances without assistance or a high top speed. I want to build a cycle with...

You are wondering how fast you can drive your bike but not get your feet wet when the road is full of water? The answer is simple: about 2.5m/s (meters per second) or roughly 9km/h (kilometers per hour), or 5.6mph. See below for the demonstation: This is a simple physics problem which is...

Hi; I am new in this forum. I was looking for such forum and at last reached to the right one. A question is in my mind, if we drive the bike within 60km/h range, we achieve a good mileage but beyond this limit, mileage drops drastically while we cover the distance in short time as compare...

I am an electrical engineer disabled in a snow sking accident and am now a quadriplegic. I'd like to design an exercise arm bike and make it magnetically resisted because friction resisted is not conducive to minute changes in resistance. I have a magnetic resisted trainer for a road...

Homework Statement I´ll need an image to show the problem: A bike with length L is on an inclined plane, the distance between the center of gravity and center wheel centers A,B is L/2. Brakes are acting on the wheels so we have a static position. In the picture is possible to...

how to select motor for electric bike?

Long story short I am deleting the exhaust crap off my bike to do so I need to trick my ECU into thinking its still there. I need you guys to help me figure out what I need to do so... Please refer to paint shop drawing If you could talk me though it or draw me up something It would be much...

Can some one please tell me the equation needed to caculate the torque needed 1. to overcome gravity trying to make you roll down hill and 2. ride up hill at 10km/h for a 100kg (bike & rider) on a bike with 66cm wheels on a 10' slope? cheers stan

Homework Statement A bicycle is rolling down a circular portion of a path; this portion of the path has a radius of 7.78 m. As the drawing illustrates, the angular displacement of the bicycle is 0.877 rad. What is the angle (in radians) through which each bicycle wheel (radius = 0.330 m)...

Hey, guys, my first time posting here but I need some educated individuals to definitively solve a problem from another forum. We are having a discussion about a bike on an incline treadmill (one presumably made for a bike). My contention is that it would still be relatively easy to pedal on...

http://img404.imageshack.us/img404/9523/dynamos.jpg I understand that when the rotating magnet spins, current should be induced in the coils which powers the lights. So what is the point of the soft iron core? The rotating magnet should magnetise it because it is near it, and it should...

I recently took a curb harder than I should've and my bike's rear tire now has a flat spot. Since my tools are currently all elsewhere I can't fix it myself. When I took it into the local bike shop the tech said that it was too badly bent to fix by simply adjusting the spokes (I agree with...

first off: hello, I'm new here. Homework Statement This is more of a personal quest than homework, a problem that I made into homework for myself. I set out to determine the equation(s) needed to determine speeds on a mountain bike at the bottom of dirt hills of varying grades and lengths...

Help needed for this question -- Air pressure in a bike tire Homework Statement The Pressure gauge on a bike pump reads 8 bar at sea level on a day when the temperature is 21°C. Assume that the gas constant for air is 286.9 J/Kg K a) What is the density of the air in the tyre? b) What is the...

Homework Statement What power must a man of mass 85 kg have to bicycle 850m up a hill, inclined at 5.2° to the horizontal, at a constant speed of 15.6m/s? The force of friction on the man and the bicycle is 175N parallel to the incline.Homework Equations The Attempt at a Solution m= 85kg...

hey mechies, i know "compressed air powered bike" is one of the oldest concept of our engineers but still in their developing stage.. i am in my final year of mechanical engineering undergraduate course. And i am about to do final project by end of this year.. when searching for real time...

Hi! I thought of motorizing my 2 wheeler. 1) Now i want to know how much Voltage (DC motor) is required to turn my wheel. 2) The source of energy? (Maybe Electric). If electric, I know it will be difficult to use batteries to run the motor. Considering car batteries, they are just too...

Hi, I have conducted a few simple experiments involving a very ordinary, road going bike wheel. I came up with a value for the moment of inertia of 0.17kgm2 I really have no idea if I am in the right ballpark with that value, would anybody be able to enlighten me as to if that is a feasible...

Hi all, Would appreciate some help with the magnetics in a contactless dynamo I'm trying to build for my road bike to power some LED lights. I've got 8 rare-earth magnets mounted on the bike wheel, near the hub. They're flat, round magnets, around 2cm dia., mounted all the way around the...

I need to sell my bike to help pay for a new car. I'm trying to get an idea for what it's worth. It's a 2006 Ninja 650R with 12,500 miles on it. I laid it down once a few years ago, but I have sliders on it so the damage is minimal. The pictures are an accurate reflection of the damage. The full...

A bike "B1" is on the go. Another one, "B2" is standing upright and still. Which one is more stable, in the sense that, if I push one, which one shall fall down more easily?

Dear All This is a rather strange question for you one that i can find no conclusive argument to. when riding a large motorbike i am informed that the engine must be reved at low speeds in order to keep the engine spinning at a sufficient speed to enable it to generate a strong enough...

Homework Statement riding his bike with v=(8.4m/s,25 degrees north of east) for ten minutes. how far to the north of the starting position did he end up? Homework Equations x=v^2sin2angle/g The Attempt at a Solution 70.56sin50/g theres not even a t in this.

As soon as a traffic light turns green, a car speeds up from rest to 50.0 mi/h with constant acceleration 9.00 mi/h/s. In the adjoining bicycle lane, a cyclist speeds up from rest to 20.0 mi/h with constant acceleration 13.0 mi/h/s. Each vehicle maintains constant velocity after reaching its...

Do any students here (or faculty for that matter) actually ride a bicycle to class? For the past few weeks I have been thinking it's a good idea. I live something like 2 miles from my university, and there are virtually no busy intersections that I would have to cross. Lately, traffic has...

So every mountain biker or motocross rider knows to never grab the front brake in the air. When you do the front end drops and can potentially ruin your day in a hurry. I figure that due to the loss of rotational inertia gravity accelerates the front wheel more rapidly, but I would like to see...

Here is a question for the physics experts. Some people been debating about the impact force on a bike of a bike rider riding off a 6 foot drop to a flat landing. Mainly the debate is about if speed would lessen the impact force on the bike because of the impact angle. So, if a bike rider...

Homework Statement Contador climbs a 5 degree section of road for 8.2 km to the summit in 20 minutes 35 seconds. he is 62kg? his bike is 8kg and the resistance force is 21 N What is the applied force needed for contador to move at constant speed? what is the work done to reach the...

Hello, I read this article about someone who made a hover bike prototype from a motorbike and two propellers. Best part is, its classified as Ultralight and doesn't require a license to fly! I can totally see myself building something like that in my back garden! How can I calculate the...

Bike and Car both accelerate from rest ("intermediate" problem) Homework Statement Basically, both a bike and car start from rest. The bike will not go any faster than (final velocity) 20 mi / hr. The car will not go faster than (final velocity) 50 mi / hr. However, at first, the bike is...

My Question... To find the maximum deflection of this axle, can the formula: (W*a/24*E*I)*(3*l^2-4*a^2) Will the total length simply be 370mm(wheel to wheel), or will I have to include the total length of the axle?

Homework Statement Your bicycle tires have a radius of 0.33 m. It takes you 850 seconds to ride 14 times counterclockwise around a circular track of radius 73 m at a constant speed. (a) What is the angular velocity of the bicycle around the track? (b) What is the magnitude of the angular...

Our local YMCA is putting on an indoor triathlon and I am trying to come up with a formula to help them determine the winner of the cycle segment. The indoor triathlon consists of a 10 minute pool swim, a 20 minute cycle on an indoor, stationary bike, and a 20 minute run on the treadmill. The...

Please, may I ask for a comment on my idea for the Aero Bike? I want to store energy in the frame of the bike, by pumping with your arms on the handlebars to create air pressure, (at the same time as you do your normal pedaling). Also perhaps regenerative braking can store energy too...

My friend asked me that this morning but I couldn't think of the answer. I know there's probably some major physical law behind it, but so many to choose from! Can you guys help me clarify this issue for myself and my friend?(when I say "riding a bike" - I mean riding on a bike. When I say...

well I am doing a project in my physics class where i have to create a device for an egg to survive a 11m fall. i created a device similar to that of a bike helmet. its been tested and it works but now i have to discuss the reason why it works. i need to include physics principles and the...

Homework Statement Jonathan is riding a bicycle and encounters a hill of height h. At the base of the hill, he is traveling at a speed vi. When he reaches the top of the hill, he is traveling at a speed vf. Jonathan and his bicycle together have a mass m. Ignore friction in the bicycle...

Hey there I'm wondering why it's remarkably more exhausting to ride a bike with a flat tire, compared to a bike with a hard inflated tire. The friction force "killing my efforts" so to speak, should be the same; the normal force is the same (my mass doesn't change), and the friction...

1. Homework Statement {Number 5 on attachment. It has picture.} When a spinning bike wheel is placed hor- izontally, hung from a pivot at one end, the axis of rotation of the wheel will swing in a horizontal circle. In which direction does it turn (as viewed from above)? 1...

Homework Statement {Number 5 on attachment. It has picture.} When a spinning bike wheel is placed hor- izontally, hung from a pivot at one end, the axis of rotation of the wheel will swing in a horizontal circle. In which direction does it turn (as viewed from above)? 1. downward...

So, what kind of judgement could they get against a 4 year old? Can they get a judgement against future income? Put the careless kid in reform school? The article makes it sound like the judge feels the child intentionally or carelessly rammed her bike into the old woman, which may have...