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forces =help

https://postimg.org/image/3zxlre5j8b/ <<this one
Original post by fara.a


describe how the acceleration changes essentially. At least thats my reading of it.
Original post by fara.a


What are you stuck on?

Describe the axes of the graph (velocity / time) and that the gradient shows acceleration (rate at which velocity changes).

Describe how the acceleration changes by referring to the gradient and state the factors affecting the acceleration. i.e. initially between the first two points, acceleration remains relatively constant but as velocity increases, acceleration reduces. Why?

After the second point, acceleration falls to zero and the velocity remains constant. Why?

You could also reference how drag on the rider is affected by surface area and therefore to maximise performance, this needs to be minimised.

Also reference friction and where this applies. I,e, road wheels on the tarmac, loose gravel, mechanical parts like wheel bearings, pedal bearings, gear linkages etc.
(edited 6 years ago)
Original post by fara.a


The faster that they go, the more air resistance it will be. As the speed increases, it accelerates at a slower and slower rate as there is more and more air resistance. The cyclist soon reaches a constant speed where the force applied to the pedals is equal to the force of air resistance.

For example, right now I am at 0 mph so I am not pushing against any air so there is no resistance. However, when I run at 10 mph I am pushing against air, so there is more resistance. Cars are designed to be streamline because, due to their high speeds, there is a lot of air resistance.

The answer I would write would be "The velocity between X and Y increases at an increasingly slower rate as with added speed comes increased air resistance, therefore slowing the rate at which velocity can increase. Between Y and Z, the velocity stays at a constant speed because the force of friction from the wheels is equal to the the amount of force from air resistance dragging the cyclist in the opposite direction, and therefore the resultant force is 0 and the cyclist maintains a constant velocity." My answer was probably a bit wordy though, so you should try to condense it into fewer words.

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