It only takes a minute to sign up. Connect and share knowledge within a single location that is structured and easy to search. In a circular motion, like the horse rides in a merry-go-round, there is only one force that acting on it, the centripetal force that pulls the ride inward.
I'm struggling to answer why the horse rides swing outward instead? The only REAL force is the centripetal force. A merry-go-round is a non-inertial frame of reference and there are inertial forces present in it too. The centrifugal force , The Euler force and the Coriolis force. The first one for example, from an observer's point of view, who is sitting in the middle of the merry-go-round pushes the object Horse in this case far from the center.
As the ride starts, The Euler force will be the apparent force pushing the person to the back of the horse, and as the ride comes to a stop, it will be the apparent force pushing the person towards the front of the horse.
You can read about these forces and the Coriolis force, which is a major player in the earth climate and weather changes, in the provided links or analytical mechanics books like "Classical Dynamics of Particles and Systems" by Thornton and Marion. Or Fowles analytical mechanics.
As you clearly understand, the horses need an inward centripetal force to undergo circular motion. But they can't get this if they are hanging vertically, or tilting inwards. Draw a free body diagram, and it's a good idea to have the horse swinging on an eye or loop that cannot transmit torque when you do this. Either this, or simply hang them on ideal strings that can support no transverse forces. In either of these cases there are only two forces: gravity, and a force tension directed along the tether.
The only one of these two that can provide the necessary inwards force the horizontal component is the tension. The horses must therefore tilt outwards. The force to the left sensed by car passengers is an inertial force having no physical origin it is due purely to the inertia of the passenger, not to some physical cause such as tension, friction, or gravitation. The car, as well as the driver, is actually accelerating to the right.
This inertial force is said to be an inertial force because it does not have a physical origin, such as gravity. A physicist will choose whatever reference frame is most convenient for the situation being analyzed.
Noninertial accelerated frames of reference are used when it is useful to do so. Different frames of reference must be considered in discussing the motion of an astronaut in a spacecraft traveling at speeds near the speed of light, as you will appreciate in the study of the special theory of relativity. Let us now take a mental ride on a merry-go-round—specifically, a rapidly rotating playground merry-go-round Figure.
You take the merry-go-round to be your frame of reference because you rotate together. When rotating in that noninertial frame of reference, you feel an inertial force that tends to throw you off; this is often referred to as a centrifugal force not to be confused with centripetal force. Centrifugal force is a commonly used term, but it does not actually exist. You must hang on tightly to counteract your inertia which people often refer to as centrifugal force.
But the force you exert acts toward the center of the circle. This inertial effect, carrying you away from the center of rotation if there is no centripetal force to cause circular motion, is put to good use in centrifuges Figure. A centrifuge spins a sample very rapidly, as mentioned earlier in this chapter. Viewed from the rotating frame of reference, the inertial force throws particles outward, hastening their sedimentation.
The greater the angular velocity, the greater the centrifugal force. But what really happens is that the inertia of the particles carries them along a line tangent to the circle while the test tube is forced in a circular path by a centripetal force.
Let us now consider what happens if something moves in a rotating frame of reference. For example, what if you slide a ball directly away from the center of the merry-go-round, as shown in Figure? A person standing next to the merry-go-round sees the ball moving straight and the merry-go-round rotating underneath it.
Up until now, we have considered Earth to be an inertial frame of reference with little or no worry about effects due to its rotation. Yet such effects do exist—in the rotation of weather systems, for example.
Viewed from above the North Pole, Earth rotates counterclockwise, as does the merry-go-round in Figure. Just the opposite occurs in the Southern Hemisphere; there, the force is to the left.
The Coriolis force causes hurricanes in the Northern Hemisphere to rotate in the counterclockwise direction, whereas tropical cyclones in the Southern Hemisphere rotate in the clockwise direction. The terms hurricane, typhoon, and tropical storm are regionally specific names for cyclones, which are storm systems characterized by low pressure centers, strong winds, and heavy rains. Figure helps show how these rotations take place.
Air flows toward any region of low pressure, and tropical cyclones contain particularly low pressures. Thus winds flow toward the center of a tropical cyclone or a low-pressure weather system at the surface. In the Northern Hemisphere, these inward winds are deflected to the right, as shown in the figure, producing a counterclockwise circulation at the surface for low-pressure zones of any type.
Low pressure at the surface is associated with rising air, which also produces cooling and cloud formation, making low-pressure patterns quite visible from space. Conversely, wind circulation around high-pressure zones is clockwise in the Southern Hemisphere but is less visible because high pressure is associated with sinking air, producing clear skies.
The rotation of tropical cyclones and the path of a ball on a merry-go-round can just as well be explained by inertia and the rotation of the system underneath. When noninertial frames are used, inertial forces, such as the Coriolis force, must be invented to explain the curved path.
There is no identifiable physical source for these inertial forces. In an inertial frame, inertia explains the path, and no force is found to be without an identifiable source. Either view allows us to describe nature, but a view in an inertial frame is the simplest in the sense that all forces have origins and explanations.
It is perpendicular to linear velocity and has the magnitude. If you wish to reduce the stress which is related to centripetal force on high-speed tires, would you use large- or small-diameter tires? Define centripetal force. Can any type of force for example, tension, gravitational force, friction, and so on be a centripetal force?
Can any combination of forces be a centripetal force? Centripetal force is defined as any net force causing uniform circular motion. The centripetal force is not a new kind of force.
That force could be tension, gravity, friction, electrical attraction, the normal force, or any other force. Any combination of these could be the source of centripetal force, for example, the centripetal force at the top of the path of a tetherball swung through a vertical circle is the result of both tension and gravity. Race car drivers routinely cut corners, as shown below Path 2. Explain how this allows the curve to be taken at the greatest speed.
That one will be the better racing line. If the driver goes too fast around a corner using a racing line, he will still slide off the track; the key is to stay at the maximum value of static friction.
So, the driver wants maximum possible speed and maximum friction. Consider the equation for centripetal force:. Looking at this from the point of view of the driver on Path 1, we can reason this way: the sharper the turn, the smaller the turning circle; the smaller the turning circle, the larger is the required centripetal force.
If this centripetal force is not exerted, the result is a skid. Many amusement parks have rides that make vertical loops like the one shown below. For safety, the cars are attached to the rails in such a way that they cannot fall off. If the car goes over the top at just the right speed, gravity alone will supply the centripetal force.
What other force acts and what is its direction if:. The barrel of the dryer provides a centripetal force on the clothes including the water droplets to keep them moving in a circular path.
As a water droplet comes to one of the holes in the barrel, it will move in a path tangent to the circle. As a skater forms a circle, what force is responsible for making his turn? Use a free-body diagram in your answer.
Suppose a child is riding on a merry-go-round at a distance about halfway between its center and edge. She has a lunch box resting on wax paper, so that there is very little friction between it and the merry-go-round. Which path shown below will the lunch box take when she lets go? The lunch box leaves a trail in the dust on the merry-go-round. Is that trail straight, curved to the left, or curved to the right? Explain your answer. This means that the lunch box will move along a path tangent to the circle, and thus follows path B.
The dust trail will be straight. What is the direction of the force exerted on you by the car seat? Suppose a mass is moving in a circular path on a frictionless table as shown below.
The action force is the force of the string on the mass; the reaction force is the force of the mass on the string. This reaction force causes the string to stretch. Ganse, a research physicist at the University of Washington. If you are observing a rotating system from the outside, you see an inward centripetal force acting to constrain the rotating body to a circular path. However, if you are part of the rotating system, you experience an apparent centrifugal force pushing you away from the center of the circle, even though what you are actually feeling is the inward centripetal force that is keeping you from literally going off on a tangent.
If the force keeping an object in rotation is broken, such as cutting the string that holds a spinning ball, the object will fly off in a straight line, following the tangential direction.
This apparent outward force is described by Newton's Laws of Motion. Newton's First Law states that "a body at rest will remain at rest, and a body in motion will remain in motion unless it is acted upon by an external force. If a massive body is moving through space in a straight line, its inertia will cause it to continue in a straight line unless an outside force causes it to speed up, slow down or change direction. In order for it to follow a circular path without changing speed, a continuous centripetal force must be applied at a right angle to its path.
Newton's Third Law states that "for every action, there is an equal and opposite reaction. When you are in an accelerating car, the seat exerts a forward force on you just as you appear to exert a backward force on the seat. In the case of a rotating system, the centripetal force pulls the mass inward to follow a curved path, while the mass appears to push outward due to its inertia.
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