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Joshua Manley

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Newton’s First Law is also known as the law of

Newton’s second law is often described as F = MA but this is misleading and does not describe what happens when multiple forces act. For this reason, a more accurate description is that the sum of all the forces acting on a single object equals mass times acceleration; Or Fnet = MA. Forces which act in the same direction on a single object add together while forces which act in opposite directions subtract.

Explain why, if objects in motion stay in motion and objects at rest stay at rest as mentioned in the talk, your bicycle eventually comes to a stop when you stop pedaling. Hint: Which forces are responsible for stopping you?

Force is the product of

In the last sentence of the talk I mention that the earth barely moves backwards as your bicycle wheel pushes against it. Does the earth really move backwards? Explain, using your understanding of Newton’s Second Law, how this could be true.

According to Newton’s Third Law, for every action there is an equal and opposite

In the Tour De France, Bicycles are designed to be extremely light, and nearly all competitors bicycles today weigh just 6.8 kg or 15 pounds. Why would it be a disadvantage for cyclists in this race to ride heavier bicycles? Use Newtons Laws to explain your answer.

If an object is at rest, what must be applied to get it moving?

According to the video, why would it be really difficult to pedal a 10,000 pound bicycle?

Additional Resources for you to Explore
There was this fellow in England named Sir Isaac Newton. A little bit stuffy, bad hair, but quite an intelligent guy. He worked on developing both calculus and physics at the same time. In his work, he came up with the three basic ideas that we still use to describe the physics of motion (up to a point). The ideas have been tested and verified so many times over the years that scientists now call them Newton's Three Laws of Motion.

It is helpful when describing forces acting on an object to label their direction. Since forces have both Magnitude (Size) and direction, they are said to be vector quantities. Vectors are represented by arrows and can be added if they face in the same direction or subtracted if they are in the opposite directions. Vector diagrams are pictures which include vector arrows to represent all of the forces which act on a single object.

Draw a vector diagram of a bicycle being pedaled and label all of the forces which act on it. If you are unsure about all of the forces that act, search google to help you figure out which forces act and then label them with arrows in your diagram.

Bicycle with thick tires, like mountain bikes, tend to go slower than bicycles with thin tires, like road bikes, when you apply the same amount of force, even if the bicycles are the same weight. This is due to the frictional force between the road and the tire.

According the the conservation of energy theory, energy cannot be created or destroyed. However, since the bicycle with smaller tires is traveling faster than the bicycle with the larger tires, it has more kinetic energy (the energy of movement). Where does this excess energy go?

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