Physics of Stopping a Bike :: physics bicycle

In short brakes ar a tool that turn energizing capability into inflame(http//en.wikipedia.org/wiki/Brakes). This is accomplished by applying clangour in one way or another. In the role of disk brakes friction is created because the braking mechanism exerts a ram down on the break pads which pushes them into contact with disk. It is this contact combined with the fact that the disks are rotating that causes energising sinew to be converted to heat. If the purpose of brakes is to convert kinetic energy into heat, then in order to hold up how much heat the brakes make requires that we find out how much kinetic energy there is in a moving roll. The important thing to know about an object that is moving on wheels is that its kinetic energy is stir to half of its mass including the wheels(Mb) multiplied by the square of its velocity(V) plus the kinetic energy in the rotating wheels. In this case I am waiver to assume that all of the mass of the wheels is located o n the outer sharpness (this isnt really the case, but most of the mass is there). Then the kinetic energy of a wheel due to rotation is half of its mass(Mw) multiplied by the square of its gas constant(r) multiplied by the square of its angular velocity(w) multiplied by two since there are two wheels. kinetic energy of the bicycle = MbV2 + 2Mwr2w2 Since the velocity of an object rolling on wheel(s) is equal the radius of the wheel times its angular velocity we can substitute V2 in for r2w2. This substitution leaves us withkinetic energy of the bike = V2(Mw+Mb). I mentioned on the last page that we must stop the bike by bout its kinetic energy into friction. To do this, the brakes apply a eviscerate to the disk with pads. The force of this friction is equal to the total downward force (f) that the pads put on the disk(the pads are usually on each brass of the disk and crush it between them) multiplied by the coefficient of friction(u).force of friction = (f)(u) For o ur purposes, while a bike is coasting the only things besides pedaling that can marrow its speed are the force of friction from the brakes and gravity.