Aboy is riding a bicycle at a velocity of 5.0 m/s. he applies the brakes and uniformly decelerates to a stop at a rate of 2.5 m/s. how long does it take for the bicycle to stop.

The working equation would be Vf (final velocity) = Vi (initial velocity) + a (acceleration) t (time). The given data are the initial velocity (5.0 m/s), acceleration (-2.5 m/s^2, negative since it is said to decelerate) and the final velocity (0 m/s, since it will put to a stop). The time would be 2 seconds. 

in most common fires, oxygen is needed for an oxidation reaction to takes place. the combination of oxygen with any element as fuel can create fire and combustion will occur especially if wood, light materials and other combustible things are combine with oxygen.