|
Energetic Transformations in Nature
|
- Energy can be converted from one form to another. Numerous instances in nature showcase such conversions.
|
|
Various Forms of Energy:
|
- Energy exists in various forms: mechanical (potential + kinetic), heat, chemical, electrical, and light.
|
|
Kinetic Energy through Examples and Equations
|
- Kinetic energy pertains to objects in motion.
- Examples: Include a moving bullet, flowing water, or a running athlete.
- Depend on Speed: The kinetic energy of an object increases with its speed.
- The kinetic energy of a body is equivalent to the work done on it to achieve its current velocity.
- Equational Representation: Kinetic energy can be represented by the equation: Ek = ½ mv2 where Ek is the kinetic energy, m is the mass, and v is the velocity.
|
|
Potential Energy: Stored Energy through Examples and Concepts
|
-
- Energy stored in an object due to the work done on it, without causing a change in its velocity, is termed as potential energy.
- Examples:
-
- Stretching a rubber band stores potential energy within it .
- Winding the key of a toy car stores potential energy in the spring inside the toy.
- The potential energy an object possesses is because of its position or configuration.
|
|
Heights of Energy: Gravitational Potential through Work and Elevation
|
-
- Gravitational Potential Energy: Gravitational potential energy of an object at a height is defined by the amount of work done to raise it from ground level to that height against the gravitational force.
- Determining Gravitational Potential Energy:
-
-
- Consider an object of mass m. Let it be raised through a height h from the ground.
- The minimum force required to lift the object is its weight, which is mg (where g is the acceleration due to gravity).
- Work done, W, on the object against gravity is:
- W = mg × h = mgh
-
- The energy gained by the object, which is its potential energy Ep, is then: Ep=mgh
- Note: The potential energy of an object at a height is relative to the ground or zero level chosen.
- An object’s potential energy can differ depending on the reference level.
- The work done by gravity on an object only depends on the difference in its vertical heights between initial and final positions, irrespective of the path taken.
- For instance, from the above diagram, if a block is raised from position A to B via two different paths, but the height AB=h, the work done in both cases remains mgh.
|
