Tuesday, November 20, 2012

Centri-WHAT?!

We've discussed two new forces recently that aren't actually "new" or "forces." Centrifugal "force" is your perception of inertia/momentum's effect on you when going in a circle -- there's no actual force pushing you outwards.
Centripetal force isn't a "new" force at all, but simply a description of whatever happens to be holding something in its circular motion -- gravity, tension, air pressure, etc.

Riddle me this, what is the cetripetal-type force that allows a car to go around a turn rather than flying off in a straight line? Briefly explain why/how the force acts in a centripetal ("center-seeking") manner.

Hint: What matters most is where the rubber meets the road.
 
 

34 comments:

  1. When a car goes out of control it spins, instead of going out in a straight line. I think this is because of the friction between the rubber and the road. These to surfaces are connected, and the ground is not a springboard, so it abosrbs the car's impact and the friction created causes the car's center to spin around itself. Also, the weight of the back of the car is heavier than the front, causing an inbalance. This inbalance helps the momentum of the spinning. The friction, however,is the centripetal-type force that makes the car spin around. If the surface was covered with something different, like tar, it would not spin at all, it would stick. In that case, the friction would not act as a centripetal force.

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  2. When the driver turns the car, he/she is directing the molecules of the tire of the car to push off from the ground in a different direction. So really the car is constantly going diagonally giving it the appearance that it is curving. Centripetal-forces are just other types of force performing work. The force doing work here is kinetic friction.

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  3. The forces that allow a car to go around a turn rather than flying off in a straight line are the tires. The tires act centripetally by directing and pulling the car in an arc rather than letting it continue/go in a straight line.

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  4. Like centrifugal force, centripetal force is not really a "force." Centripetal "force" is the description of whatever happens to be holding something in its circular motion, motion that is unnatural and has to be constantly pulled inward by some outside force. In regards to the centripetal-type force that allows a car to go around a turn rather than flying off in a straight line, I believe acceleration caused by the tire movement and also the tension caused by the friction between the road and the tires is involved. When a car turns, the front wheels turn more sharply than the back wheels, quickly guiding the car into the curve. Even though the car wants to keep going in a straight line, this change in acceleration helps to guide the car around the curve in a circular motion. Also, the tire rotation on the road creates more friction and therefore tension between the road and the tires. This is also a contributing centripetal-type force that allows the car to travel around the corner rather than flying off in a straight line.

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  5. I think that since "centrifugal force"-or really the misinterpretation of inertia and momentum-needs an obstruction to halt the object that is moving, the molecules of the rubber tires rubbing against those of the gravel cause kinetic friction to slow the car down and not make it divert off-course by going in a straight line, thus acting as a centripetal force pulling the car unnaturally towards the center/inward and making it stay on track. The ground provides tension for the tires of the car as well, thereby causing the car to decelerate and start to change direction and speed (velocity). Further, I think that the ground acts as a normal force to counteract and absorb some of the impact of the rubber tires grinding into the ground, causing the car to turn and move in an angular motion rather than keep going straight.

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  6. The centripetal "force" that allows the car to turn rather than going straight off the curve is a combination of the tire's change in direction and the friction and tension between the tire and the road. The car is guided by its wheels and when the wheels turn, the car wants to keep going straight. (For example: if you turn really hard, the car jerks really hard in the opposite direction of the wheels. ) However, the car is CONTROLLED by the wheels. When the tires turn against the road, they apply a pressure against the road, preventing the car from doing in that direction. That's what causes the car to turn. Friction prevents the car from going straight, not a centripetal force. The back of the car, being lead by the front of the car, swings around heavily, adding the the illusion of a centripetal force.

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  7. The car follows the curve because the driver wills it to follow the curve - if left to its own devices, the car might continue to roll forward off of the road, however by turning the steering wheel, the driver also turns the WHEELS of the car. the wheels control the direction that the car moves in (this is why when parking on a slope, it is advised to turn the wheels towards the curb! because if the car suddenly started to move, the turned wheels would cause it to move forward into the curb instead of straight down a hill). Therefore, the "centripetal force" leading to the car following the curve is actually the tire change in DIRECTION. The body of the car may wish to continue in a straight line, but the tires are like the resistant force of the inside of ones car in a friendly game of car jello - you want to keep moving forward, much like the body of the car, but the car door stops you, much like the tires. Velocity must change at a curve.

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  8. The centripetal force that allows the race car to go around a turn instead of flying off in a straight line are the alignment of the tires. The alignment of the tires on the race car in fact have a centripetal force. Thus allowing the direction of the race car to be adjusted, so that the car does not end up flying off in a straight line. Instead, the race car is able to make the turn smoothly, with the assistance of centripetal force.The contact between the tires and the road helps the centripetal force take place as well.

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  9. The driver controls the velocity of the wheels that are turning the car into a circular motion due to centripetal force of the friction of the tires against the ground. The centrifugal inertia of the car wants it to veer the way it was going (straight) rather than going in to the turn. The force pushing the driver left or right is actually the inertia of his body wanting to stay in the same line it had been traveling in before the turn.

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  10. As the car turns around a corner, the force of the tires pushes off of the force from the ground which allows the car to turn instead of go in a straight line. Therefore, the force of the tires against the force of the ground in the centripetal-like force that allows the car to turn instead of continuing straight.

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  11. The grooves of the tire are what allow the car to go around a turn rather than flying off in a straight line. Even though the tire turns in a circular motion, it still has its own inertia. As the driver turns the car, the rubber grooves of the tire against the ground (friction) allow the car to turn safely. If the tires had their own way, they would follow their own inertia and go straight, but since there is friction working with the tires grooves against the ground, it unnaturally keeps the car on course (along with the control of the driver) while turning, thus acting as a centripetal force. Therefore, it is the tires’ particles, or friction, that acts as the centripetal force in keeping the car from going off in a straight line when turning.

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  12. When a car is in drive the ridges of the tire and the ridges of the ground are rolling along together until the outside force of the person moving the steering wheel causes the car to turn which moves the tire's ridges into other ridges on the road. Even though the car wants to go straight the wheels move in a circular motion forcing it to move because it has its own inertia.

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  13. The curve of the road pushes the car in the direction of the road, also it is the friction of the tires on the road. The centripetal force on the car pulls it to the center of the circle or center of the curve that the car is going in.

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  14. As the car turns round the bend, it still posses its own inertia. The tires are uneven and thus the imperfections of both the road and the tires together create friction that enables the car to continue on its path, which acts as a centripetal force. Friction, moreover, acts as the centripetal force in this scenario.

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  16. The centripetal force is used to help keep the car moving in a circular motion. I think the road exerts friction onto the tires. This friction between the tires and the ground is the centripetal force. As a result,'the car's direction is changed in order to keep the car pointed at the center of it's circular ark.

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  17. The person driving the car is turning the wheels which have friction with the road to help the car turn instead of continuing straight. As the tires are turning the car goes along with it, i.e. the centripetal force.

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  18. The friction between the wheel of the car and the ground keeps it from flipping. Also gravity is helping to keep it on the ground.

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  19. The traction of the tires allow the car to continue turning and not just move in a straight line. This friction produced between the tires and the road is great enough to not make the car slide into a straight line. The centripetal "force" also helps by pulling the car toward the center of the direction it is turning.

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  20. The centripetal force is affecting the wheels of the turning car. These forces that are connected to centripetal force, such as tension, friction, gravity, and normal force. The normal force of the ground against the rubber, which also is an elastic material, was able to slide the wheels against the friction of the ground and the wheels. The tension allowed the wheels to maintain suspension of the car while it began to turn, but since gravity is constantly pulling objects towards some kind of center, the wheels maintain to stay on the ground while the wheels are curved enough that the angular force is balanced. This will keep the car from going off the road (straight constantly), and keep the car on the road (turning at occasions).

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  21. The "Centripetal-type force", is because of the friction caused by the application of a force (gravity) on the tires, which keeps the car on the road. The friction caused by the tires is on all 4 of the tires, which means that all tires get the same amount of force applied on them towards the ground. However, since all tires get the same amount of force, but the rear tires are moving at a higher rate of speed,(due to the fact that they (rear wheels) travel more distance over the same amount of time), therefore, the rear wheels travel in an arc, with the [car's] body acting as a force preventing the rear wheels from moving in a straight line. This makes it possible for the front of the car to aim in different direction, so that the car can move in a not-straight line, and can go left or right, or anyplace in between.

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  22. The centripetal force is seem because the tires move. The four tires move at different arcs and have friction with the ground.

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  23. The force acting on the car allowing it to turn in a circle is friction from the ground's normal force and the car's tires! The normal force allows it to stay in motion in a circle along with gravity. The friction keeps it from flying off of the road.

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  24. The car wants to continue in a straight line, but the friction of the tires to the road will turn it. When the front wheels turn, the front of the car moves slower than the back of the car, causing the back end to swing around thus turning the car.

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  25. In this instance of the car turning centripital force is being utilized in order for the car to actually make the turn. Although the car wants to stay in a straight line, the friction created between the tires and ground allow the car to turn. This means that the friction the tires create with the ground as a centripital force and allow the car to make its turn.

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  26. The tires are the force that keep the car from flying off into the side of the rode. The tires are under the car, and when the car drifts, the whole car turns sideways, but the tires are staying straight. It is like when a person is in the car and the car is the only thing keeping you from flying out of the car. The same goes for the tires, keeping the car from flying out off of the street.

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  27. The centripetal force affects the turning wheels of the car. Although the car's "intention" is to go in a straight direction, the friction that is created between the ground and the tires allow the car to turn as much or as little as it pleases. Also, gravity helps keep the car firmly planted on the ground.

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  28. The tires connected to the steering wheel is the centripetal type force acting on the car that allows the car to turn around a curve instead of flying straight off. The driver uses the steering wheel to point the in direction the car needs to go, and as the wheels turn they act as the centripetal "force" causing the car to go around the curve. This change if intertia allows the car to take the turn instead of going through it and crashing.

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  29. The friction between the tires and the ground keep the car from moving in a straight line (which it naturally wants to) therefore the friction is the centripetal force allowing the car to make the turn.

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  30. I think the friction between the tires and the road allow for the car to round the bend instead of flying off the road. The centripetal force of the car being close to the center of the turn lets it move in the circular direction. Sorry for responding so late.

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  31. I think the reason the car does not fly into a straight line and spins out of control is because of the friction and direction of the tires. The tires guide the car; however, when it curves too quickly the car wants to continue into a straight line, while the wheels tell the car to turn which causes circular movement.

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  32. There are many factors that allow the car to go around a turn rather than flying off in a straight line. First off all the tires of the car guides the car which allows the driver to maintain control of the car. The wheels of the car act as an outside force which cause the car to stop going in a straight line.

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  33. The car can turn because the steering wheel is turned in the direction the driver disires and the wheels turn too. This makes the car move in the direction the wheels are pointing at. The contact of the wheels and the ground has friction occuring, this movement of the wheels changing direction makes the car turn and wants to keep it going outwards because of the centripetal force. If the wheels were detached from the car while the wheels turn, the car would go straight off the road because of its momentum.

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  34. The friction created by the tires scraping across the asphalt creates friction which forces the car into a circular motion.

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