When something is able to change its environment or itself, it has energy. When you think of energy, you might think of action- or objects in motion, like the baseball that shatters a window. There are different forms of energy. Turn on an electric light and a dark room becomes bright. Turn on a music player and sound comes through your headphones. In both situations, energy moves from one place to another; effect and reaction. The two different types of energy are kinetic and potential energy.

Kinetic energy is the energy a moving object has because of its motion. The kinetic energy of a moving object depends on the object’s mass and its speed. The kinetic energy of a moving object can be calculated from this equation:

Kinetic energy (in joules) = ½ mass (in kg) x [speed (in m/s)]²

KE= ½ mv²

In this equation ^, the symbol v represents speed.

Example Find the kinetic energy of the ball having mass 0,5 kg and velocity 10m/s.

Ek=1/2mv²
Ek=1/2.0, 5. (10) ²
Ek=25joule
Stored energy due to position is called potential energy. For example, a heavy ball of a demolition machine is storing energy when it is held at an elevated position. Just as there are different types of energy, there are 3 different types of potential energy; elastic potential energy, chemical potential energy, and gravitational potential energy. Elastic potential energy is energy stored by something that can stretch or compress, such as a rubber band or spring. Energy stored in chemical bonds is chemical potential energy. [pic]

Energy is stored in the bonds that hold the carbon and hydrogen atoms together and is released when the gas burned. Gravitational potential energy (GPE) is energy stored y objects due to their position above Earth’s surface. The GPE of an object depends on the object’s mass and height above the ground. GPE can be calculated using the following equation:

GPE (J) =

Mass (kg) * acceleration of gravity (m/s²) * height (m)

...PotentialEnergy
• Definition and Mathematics of Work
• Calculating the Amount of Work Done by Forces
• PotentialEnergy
• KineticEnergy
• Mechanical Energy
• Power
An object can store energy as the result of its position. For example, the heavy ball of a demolition machine is storing energy when it is held at an elevated position. This storedenergy of position is referred to as potentialenergy. Similarly, a drawn bow is able to store energy as the result of its position. When assuming its usual position (i.e., when not drawn), there is no energy stored in the bow. Yet when its position is altered from its usual equilibrium position, the bow is able to store energy by virtue of its position. This stored energy of position is referred to as potentialenergy. Potentialenergy is the stored energy of position possessed by an object.
Gravitational PotentialEnergy
The two examples above illustrate the two forms of potentialenergy to be discussed in this course - gravitational potentialenergy and elastic potentialenergy. Gravitational potential...

...system. |
| | It would take less time to reach its bound orbit. |
| | It would orbit the earth at a faster velocity. |
| | | | |
Question 7 | 1.61 points | Save |
| When energy is converted from one form to another, a tiny amount is inevitably lost. | | | | |
| | True |
| False |
| | | | |
Question 8 | 1.61 points | Save |
| There is no gravity in space. | | | | |
| | True |
| False |
| | | | |
Question 9 | 1.61 points | Save |
| The Moon is slowly moving away from the earth. | | | | |
| | True |
| False |
| | | | |
Question 10 | 1.61 points | Save |
| Which of the following statements correctly describes the law of conservation of energy? | | | | |
| | | The total quantity of energy in the universe never changes. |
| | An object always has the same amount of energy. |
| | It is not really possible for an object to gain or lose potentialenergy, because energy cannot be destroyed. |
| | Energy can change between many different forms, such as potential, kinetic, and thermal, but it is ultimately destroyed. |
| | The fact that you can fuse hydrogen into helium to produce energy means that helium can be turned into hydrogen to produce energy. |
| | | | |...

...the transfer of energy; work is done on an object when an applied force moves it through a distance. The link between work and energy is work done equals energy transferred. The units for the two are also the same (joules). E.g. 500J of work = 500J of kineticenergy.
Work is calculated with the formula: work done=force x distance moved
For example, if a force of 10 newton (F = 10 N) acts along point that travels 2 meters (d = 2 m), then it does the work W = (10 N)(2 m) = 20 N m = 20 J. This is approximately the work done lifting a 1 kg weight from ground to over a person's head against the force of gravity. Notice that the work is doubled either by lifting twice the weight the same distance or by lifting the same weight twice the distance.
Examples:
Force is measured in newton’s (N)
Distance is measured in meters (M)
Work done is measured in joules (J)
Examples of work done:
How much work is done by a person who uses a force of 27.5N to move a grocery buggy 12.3m?
W = F x d = (27.5N) (12.3m) = ?
Equation
W = 338.25J
Answer
55, 000J of work is done to move a rock 25m. How much force was applied?
F = W = 55,000J = ?
d 25m
Equation
F = 2200J
Answer
You and 3 friends apply a combined force of 489.5N to push a piano. The amount of work done is 1762.2J. What distance did the piano move?
Equation
d= W = 1762.2J =
F 489.5N
Answer...

...KINETICENERGY
Objects have energy because of their motion; this energy is called kineticenergy. Kineticenergy of the objects having mass m and velocity v can be calculated with the formula given below;
K=1/2mv²
Kineticenergy is a scalar quantity; it does not have a direction. Unlike velocity, acceleration, force, and momentum, thekineticenergy of an object is completely described by magnitude alone. Like work and potentialenergy, the standard metric unit of measurement for kineticenergy is the Joule. As might be implied by the above equation, 1 Joule is equivalent to 1 kg(m/s) 2.
Examples
1. Determine the kineticenergy of a 625-kg roller coaster car that is moving with a speed of 18.3 m/s.
Answer:
KE = 0.5mv2
KE = (0.5)(625 kg)(18.3 m/s)2
KE = 1.05 x105 Joules
2. If the roller coaster car in the above problem were moving with twice the speed, then what would be its new kineticenergy?
Answer:
KE = 0.5mv2
KE = 0.5(625 kg)(36.6 m/s)2
KE = 4.19 x 105 Joules
Work-Energy Theorem
Relationship between KE and W: The word...

...has mass 2.0 x 10 kg. When the sphere is released, it eventually
falls in the liquid with a constant speed of 6.0 cm s .
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1. its kineticenergy,
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kineticenergy = ...................................... J
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2. its rate of loss of gravitational potentialenergy.
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rate = ...................................... J s
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losing potentialenergy at a steady rate.
......................................................................................................................................

...an gravitational field except with the Principle of Equivalence.
PotentialEnergyPotentialenergy is the same as stored energy. The "stored" energy is held within the gravitational field. When you lift a heavy object you exert energy which later will become kineticenergy when the object is dropped. A lift motor from a roller coaster exertspotentialenergy when lifting the train to the top of the hill. The higher the train is lifted by the motor the more potentialenergy is produced; thus, forming a greater amount if kineticenergy when the train is dropped. At the top of the hills the train has a huge amount of potentialenergy, but it has very little kineticenergy.
KineticEnergy
The word "kinetic" is derived from the Greek word meaning to move, and the word "energy" is the ability to move. Thus, "kineticenergy" is the energy of motion --it's ability to do work. The faster the body moves the more kineticenergy is produced. The greater the mass and speed of an object the more kineticenergy there will be. As the train accelerates down the hill the...

...PotentialEnergyPotentialEnergy is a type of energy that does not involve motion. It is the energy that is stored up. The more work done to change an object's position or shape, the more potentialenergy it has. For example, a person on a ladder has more potentialenergy than a person on the ground because they have done more work to get up there.KineticEnergyKineticEnergy is the energy of motion. The more work an object has done, the more kineticenergy it has. the amount of kineticenergy an object has can be calculated by the formula:
KE = 1/2 MV2
It can be defined as the works needed to accelerate an object of a certain mass from rest to its stated velocity.
Thermal Energy
Thermal Energy is the energy an object has related to temperature. It comes from all of the energy of the particles in an object. Typically, objects with a higher temperature release more thermal energy than objects with a lower temperature because their atoms and molecules move faster. Within every energy conversion, there is thermal energy emitted.Chemical Energy
Chemical Energy is the...

...WORK and ENERGY
Work done by a constant force
1- The drawing shows a plane diving toward the ground and then climbing back upward. During each of these motions, the lift force acts perpendicular to the displacement , which has the same magnitude, 1.7 × 103 m, in each case. The engines of the plane exert a thrust , which points in the direction of the displacement and has the same magnitude during the dive and the climb. The weight of the plane has a magnitude of 5.9 × 104 N. In both motions, net work is performed due to the combined action of the forces , and .
a. Is more net work done during the dive or the climb? Explain.
b. Find the difference between the net work done during the dive and the climb.
Answer:
a. More net work is done during the dive.
b. 6.8 × 107 J
2- Find the work done by a force through a displacement of 3m in the positive x direction
Work-Energy theorem and kineticenergy
3- The mass of the space probe is 474-kg and its initial velocity is 275 m/s. If the 56.0-mN force acts on the probe through a displacement of 2.42×109m, what is its final speed?
Answer:
4- Example 2: Skier
Gravitational PotentialEnergy, Conservative versus Nonconservative Forces
5- The gymnast leaves the trampoline at an initial height of 1.20 m and reaches a maximum height of 4.80 m before falling back down. What was the initial...