Is a ball rolling kinetic or potential?

Answer 1:

Are you asking about how a ball would actually rolls uphill? Or are you asking about some optical illusion, where it's not really rolling uphill? I'm not sure what you mean, but I'll explain how a ball could actually roll uphill.

Table of Contents Show

Is a rolling ball kinetic?
What type of energy is a ball rolling?
What force is rolling a ball?
Is a rolling bowling ball potential energy?

If my answer is not what you're looking for, please write me back and explain more what you're looking for.

A ball could have two different types of energy: kinetic energy or potential energy. Kinetic energy is the energy of motion. If the ball is moving, it has kinetic energy. Potential energy is stored energy, waiting to be used. If a ball is really high, it will have a lot of potential energy.

Picture two hills side by side, with a valley in the middle ,making a "U" shape. If you place a ball on the top of the left hill, it is high up, so it has potential energy. Now, if you allow it to roll down the hill, it changes that potential energy into kinetic energy (it gets less high and starts to roll faster). At the bottom of the "U", all of the potential energy has been converted to kinetic energy. As the ball continues to roll, and roll uphill on the right hill, it is converting that kinetic energy back into potential energy again.

So a ball must have kinetic energy to roll uphill. A ball that's not moving won't just start rolling uphill on its own. It doesn't have the energy. But a moving ball has kinetic energy, and can roll uphill for a while.

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Science Content: Potential Energy and Kinetic Energy

Total energy

The reason we are interested in energy is that the total energy in the universe is constant. When one object gains energy, it must have come from somewhere. This places a constraint on what can happen in any situation. In studying any event, physicists consider what happened to the energy as the first step in understanding the process.

Energy has many forms. Some are more obvious and easy to recognize than others. We have focused on energy due to gravity in the previous activities because it is uncomplicated and easy to measure.

Kinetic energy

Objects that are moving have a kind of energy called kinetic energy (which is Greek for "energy of motion"). Kinetic energy is related to mass and speed by

Kinetic Energy =1/2 mass x velocity2 .

The presence of the factor of mass means that a massive object has more kinetic energy than a less-massive object traveling at the same speed; changing the speed of a very massive object will require adding a lot of energy to it.

We can analyze the ball rolling down an incline in terms of energy, by observing that there is an unbalanced force on the ball that is transferring energy to it, and its kinetic energy is increasing correspondingly. Unfortunately, a rolling ball is not as simple as it appears: the part of the ball that is in contact with the track is temporarily not moving at all, and other parts of the ball are moving upwards or downwards, and with different speeds. The result is that the kinetic energy of the rolling ball is proportional to mv2 but the coefficient in front is not 1/2 (or we could say, the mass that appears in this equation is different from what we get when we weigh the ball). This complication is not present when we throw a ball, but now the ball is going too fast for us to measure the speed with a stopwatch over distances that will fit in a classroom.

Potential energy

When you lift a watermelon, you exert an upward force and the watermelon moves in the upward direction. Therefore you have transferred energy to it. Where is this energy? It hasn't gone far, because we can get it back by letting go! When the watermelon returns to its original height, it will have kinetic energy -- exactly the energy you gave it earlier.

But where was the energy in the meanwhile? The watermelon isn't hotter, or moving fast, or different in any visible way, except that it is higher. This points to the existence of a new kind of energy, called gravitational potential energy. It is a property of the interacting system consisting of the watermelon and the earth itself.

As you were lifting the watermelon, you were increasing the potential energy. Because the gravitational force is constant, the gravitational potential energy is just

Gravitational potential energy = weight x height

It may seem that there are two ways to use energy concepts to describe a falling object:

As the object is falling, the potential energy is being converted into kinetic energy.
When you drop the object, there is a downwards gravitational force and the object moves downwards; this transfers energy to the object.

However, these are not really different explanations. In the first explanation we are focusing on the result (energy of one form has been transformed into another), while the second explains how the transfer of energy takes place; these are the same explanation with different levels of detail, and there is just one energy contribution involved.

Energy and the "Air ball"

Is a rolling ball kinetic?

Kinetic Energy of Rolling Object If an object is rolling without slipping, then its kinetic energy can be expressed as the sum of the translational kinetic energy of its center of mass plus the rotational kinetic energy about the center of mass.

What type of energy is a ball rolling?

Kinetic energy is due to motion. So if the ball is rolling down it has kinetic energy.

What force is rolling a ball?

The forces on a rolling ball include a horizontal friction force, F , and the normal reaction force, N , acting a distance S ahead of the center of the ball.

Is a rolling bowling ball potential energy?

In a previous slide, we discussed how the potential energy of an object can change to kinetic energy. For example, when you are holding the bowling ball, it has potential energy. As you release the ball, most of its energy is kinetic. However, as the ball begins to slow its kinetic energy decreases.