At one point in your life, you might have played on a swing. Have you ever wondered why, after the first swing, it will slow dow
n and eventually stop if you do not keep moving your body? In order to understand this, you need to learn about forms of energy and their behaviors.
Forms of Energy
Energy comes in two main forms: kinetic and potential. Kinetic energy (KE) is the energy of motion. All moving objects have this type of energy. A bullet train in Japan has KE as it travels at 270 miles km/hr. You may not see or feel it, but the particles that make up your computer vibrate. Vibration is motion, which means that those particles have KE.
Which part of the picture represents KE? How do you know?
Potential energy (PE) is the energy an object has because of its position. A ball sitting on top of a slide has PE. It has stored energy and has the potential to do work.
KE is the energy of motion and PE is the energy of an object due to its position. Which type of energy do these two balls have?
PE includes gravitational PE and elastic PE. Work is needed to elevate objects against Earth’s gravity. Gravitational PE is the type of PE that results from the elevated position of an object. Elastic energy is stored in stretchable objects. For example, a bow that is pulled back has elastic PE that can be used to do work on an arrow.
Think about the difference between gravitational and elastic PE. Which type of PE does the book have?
The Law of Conservation of Energy
Now that you know about the types of energy, take a look at how energy behaves. The law of conservation of energy, also caled the first law of thermodynamics, says that energy can neither be created nor destroyed, but is just changed from one form to another. This means that whatever energy existed in the universe at the beginning of time is the same energy that remains today.
To understand how energy changes from one form to another, examine the swinging motion of a pendulum. A pendulum, also called a bob, is an object suspended from a fixed point that can swing freely. See the diagram below.
A swinging pendulum shows how gravitational PE is transferred to KE and back again.
When the bob is at the highest point of its swing at point A, it has no KE. It has the maximum amount of gravitational PE. When the bob swings downward, its gravitational PE is transformed to KE. This causes the bob to speed up.
At point B, the bottom of its swing, the KE of the bob is at a maximum. At this point, the bob has no PE.
As the bob moves upward, its KE is transformed to gravitational PE. At point C, the top of the bob’s swing, its KE is zero. Its gravitational PE is at a maximum.
The diagram also shows that the bob’s swing becomes lower as the swinging continues. This is because some of the bob’s energy is lost to the surroundings as heat.
Now, think about the swing scenario at the start of this passage. Can you identify when the energy of the swing is transferred from KE to PE and back again? Can you now understand why, after the initial swing, the swing slows down and eventually stops?
PLEASE HELP YOU WILL BE GIVEN 50 POINTS The artical above Read about Pendulums. Then complete the sentences based on the diagram of the pendulum. Be sure to keep this article open because there will be several questions related to it.
The pendulum has the most potential energy
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The pendulum has the least kinetic energy
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The pendulum has the most kinetic energy
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The pendulum has the least potential energy
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