Kinetic Energy and Potential Energy in Physics: Simple Explanation with Definition, Formulas, Units, Examples.
Kinetic and potential energy
Kinetic energy is the form of energy possessed by a moving body. The amount of kinetic energy of a body can be expressed by the relationship:
E = 1mv²
where m indicates the mass of the body and v² is the square of its velocity. In particular, if the body moves with uniformly accelerated motion, that is, if the motion occurs with constant acceleration, the kinetic energy can be written in the form:
E = (but) d
where a is the acceleration of the mass and med is the distance travelled at the instant considered.
The relationship between kinetic energy and potential energy and between the concepts of force, distance, acceleration and energy becomes intuitive if we think about how these physical quantities vary in common situations, such as the throwing of an object or the falling of a body. To lift an object from a supporting surface, for example, it is necessary to apply a vertical force, directed upwards, in order to overcome the force of gravity.
This force does work that is stored by the body in the form of energy, specifically in the form of potential energy (in this case, gravitational). If the object is dropped, the potential energy it possesses is gradually converted into kinetic energy. At the point of maximum height the body possesses only potential energy, while at the moment it hits the ground, after falling, all the energy is kinetic.
- What is meant by kinetic energy?
Kinetic energy is the energy possessed by a moving body.
- What is the difference between kinetic and potential energy?
Kinetic energy is related to the motion of a body while potential energy is related to the position of a body.
- What is the formula to find kinetic energy?
E = 1mv², where m indicates the mass of the body and v² is the square of its velocity.
- What is meant by potential energy?
Potential energy is the energy possessed by a system as a consequence of its position in a conservative force field.
Potential Energy: Definition and Explanation
Potential energy is the energy possessed by a system as a consequence of its position in a conservative force field. For example, a ball lifted from the ground has gravitational potential energy because it is subjected to the effect of the Earth’s gravitational field; the value of the potential energy in this case depends on the height of the ball above the ground. A stretched rubber band has elastic potential energy, and an electric charge placed in an electric field has electrostatic potential energy.
To provide a system with potential energy, work must be done; in fact, an effort is needed to lift a ball from the ground, to stretch a rubber band, or to bring two charges of the same sign together. The amount of potential energy that a system acquires is exactly equal to the work done to bring the system to the final condition. In conservative force fields, the principle of conservation of energy implies that the sum of potential energy and kinetic energy is constant during dynamic evolution. For example, in the case of a ball falling from a height h from the ground, the potential energy is transformed into kinetic energy during the motion (of free fall); when the ball reaches the ground, all the potential energy is transformed into kinetic energy.
Kinetic and Potential Energy: Frequently Asked Questions
Questions & Answers
- What is meant by kinetic energy?
Kinetic energy is the energy possessed by a moving body.
- What is the difference between kinetic and potential energy?
Kinetic energy is related to the motion of a body while potential energy is related to the position of a body.
- What is the formula to find kinetic energy?
E = 1mv², where m indicates the mass of the body and v² is the square of its velocity.
- What is meant by potential energy?
Potential energy is the energy possessed by a system as a consequence of its position in a conservative force field.