Why doesn't a bicycle continue to move at the same velocity forever?

Answer 1

Answer:

It's because of something called inertia.

Inertia basically means that things that are moving likes to keep moving, and things that are stationary likes to stay stationary.

The heavier something is, or the faster it moves, the more inertia it has.

Now, compared to the rider, the bicycle is quite light, so the brakes can quite easily soak up the inertia from the bike and stop the bike.

The rider OTOH has a lot more inertia and will continue to (try to) move forward.

Same thing that slams you into the seat belt when a car brakes hard.

Quick tip on riding technique - before braking hard, move your body to the rear and down, and brace your arms real well.

Answer:

In general if the tires are locked up and you want to know why your still moving it's because the momentum of your bike is greater then the 1/2 inch of tire friction that is the only contact on the ground and the tire isn't enough by itself to do any serious stopping.

Your main braking is the brake shoes or pads in combination of the tire. Think of using the whole tire as the brake, as long as it's turning you will stop far shorter then someone that has locked up their brakes.

That is basically what the Anti-Skid braking systems do on cars, they sense the tire not rotating and will release that brake just enough to keep the wheel turning.

Answer 2

Because in our physical reality there are always losses. Some energy is lost in bearings that dont spin entirely w/o resistance, some is lost to air drag and some is lost to the deformation of the tires as we sit on the bike. If you don't keep pedalling all these small losses will quite rapidly bring you to a stop.

Answer 3

Friction, inertia and your sense of balance.

Answer 4

Because of friction, in bearings, tires and air drag.

Answer 5

To overcome the losses in air drag, rolling resistance, and bearings.