An Example
Why does the roller coaster stay up?The roller coaster stays up because the centripetal force is greater than or equal to the weight of the car and the people. Both the weight and Fc vectors are pointed downward at the top. However the reaction force or normal force (Fn) is upward and equal to Fc. The inertia (urge for to travel in a straight line) of the car pushes it up (Fn) against the track with a force equal to Fc. So: Fnet = mg - Fn. The people may feel a feeling weightlessness if Fnet is 0. |
Links: & Extras | IntroductionIn uniform circular motion the magnitude of the velocity of the object in motion remains constant. For example at car turning around a circular curve will stay at 12 m/s throughout the entire turn (provided the driver does not brake). The direction of the velocity vector is changing. A force is required in uniform circular motion.Centripetal Force & AccelerationSince an object in motion will travel in a straight line (Newton 's First Law) an force must be required to accelerate the mass . This force does not cause a change in velocity as stated in the introduction, but rather it is responsible for the change in direction. The centripetal acceleration (ac) is equal to the square of the velocity (v) over the radius of the circular motion. According to Newton 's Second Law, then the centripetal force (Fc) should be the mass of the object (m) times the centripetal acceleration. The equations are pictured above.Important Facts * "Centrifugal" force is a fictitious force. It is a perceived force. There is no reactive force as per Newton 's Third Law. This the 'force ' that you feel when you take a turn in a car or on a roller coaster. If this was a real force, then when your car slips on ice or the roller coaster your on breaks, you should fly outward perpendicular to the direction of your motion. Obviously this is not true. * If the centripetal force is removed, the object will continue on a path tangent to the circle. In other words, you should continue in a straight line in the same direction at the motion at the exact instant the centripetal force is removed. * The centripetal force vector always points to the center of the circlar motion. * The centripetal could be the tension in a string, gravity (for simple planetary orbit like in simulation), friction (i.e. the car on pavement), or other force. This equivalency is very helpful for our calculations. See table below: Force | Equation | Info | Tension | | Like a string or other physical connection. i.e. Swinging keys on a lanyard. The keys are the mass and the Fc is equal to the tension in the lanyard. | Gravity | | Gravity keeps items planets and moons in orbit (a simple form of uniform circ. motion). There is not physical connection. See Newton 's Law of Universal Graivitation | Friction | | Friction is the only thing keeping cars from spinning out at every turn. In icy conditions there is little friction and so you have to keep your speed low or else you will spin out of your turns. | An Example Why does the roller coaster stay up?The roller coaster stays up because the centripetal force is greater than or equal to the weight of the car and the people. Both the weight and Fc vectors are pointed downward at the top. However the reaction force or normal force (Fn) is upward and equal to Fc. The inertia (urge for to travel in a straight line) of the car pushes it up (Fn) against the track with a force equal to Fc. So: Fnet = mg - Fn. The people may feel a feeling weightlessness if Fnet is 0. |
You May Also Find These Documents Helpful
-
Centrifugal force - the tendency of rotating object to flee from the center of their rotation…
- 1465 Words
- 6 Pages
Better Essays -
W = mg where W = weight, m = mass, g = acceleration due to gravity.…
- 7664 Words
- 31 Pages
Better Essays -
Vocabulary: acceleration, centripetal acceleration, centripetal force, Newton’s first law, Newton’s second law, uniform circular motion, vector, velocity…
- 1444 Words
- 6 Pages
Satisfactory Essays -
6. Centripetal Force- This is a force that pulls from the center of the car when in a circular motion. It’s the opposite of centrifugal force and does increase with acceleration.…
- 484 Words
- 2 Pages
Satisfactory Essays -
Earth pulls on the moon and holds the moon in its orbit. The moon pulls on Earth with an equal and opposite force. This is an example of Express the following as an equation: One newton is the force that can give an object with a mass of 1 kg an acceleration of 1 m/s2.…
- 832 Words
- 4 Pages
Good Essays -
Mass is a measure of the amount of matter in an object, it is measured in kilograms (kg). The weight of an object is a measure of the force with which it is attracted by a gravitational force, it is measured in Newtons (N). It is directly related to the strength of the gravitational field at a point where the object is located. W=mg…
- 32437 Words
- 130 Pages
Powerful Essays -
7. Centrifugal Force- the force that pulls out from the center on a body in circular motion.…
- 499 Words
- 2 Pages
Good Essays -
Weight is the force of gravity acting on an object’s mass measured in newtons (N). Weight is a force thus a vector quantity.…
- 4988 Words
- 20 Pages
Powerful Essays -
8. Centripetal Force-a force that pulls an object that's moving in a circular motion going towards the center…
- 314 Words
- 2 Pages
Satisfactory Essays -
In this activity, you will explore the acceleration of an object that travels a circular path at constant speed. Motion of this kind is called uniform circular motion.…
- 3043 Words
- 10 Pages
Satisfactory Essays -
Centripetal acceleration: it is one of the most important elements to consider in rollercoasters. It is what keeps you in the cart on turns and makes you feel weightless at the tops of large hills. Centripetal acceleration is generally described through…
- 559 Words
- 3 Pages
Good Essays -
Vocabulary: Please define six (6) of the following terms in your own words. Please do not just copy and paste the definition.…
- 438 Words
- 2 Pages
Good Essays -
7. Centrifugal Force- the apparent force that draws a rotating body away from the center of rotation; caused by the inertia of the body as the body's path is continually redirected…
- 476 Words
- 2 Pages
Good Essays -
Did you know that almost all roller coasters only rely on Earth’s gravity to get the cars down the track? Roller coasters are centered all on physics and I will hopefully teach you some things, big or small about them today. In this essay we will be exploring the world of roller coasters. Some of the topics we will cover will range from the history, to the principles that allow the cars to continue throughout the length of the track, and the general physics surrounding roller coasters.…
- 1672 Words
- 7 Pages
Better Essays -
3.) The roller coaster is on top of the track, the track applies a opposite or equal force on the roller coaster.…
- 122 Words
- 1 Page
Satisfactory Essays