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Physical Science. Physics experiment: mechanical energy: Resources

Task - Science, Physics, Year 10

Design and conduct an experiment to prove that the conservation of mechanical energy can be applied to pendulum motion by comparing the theoretical and actual velocity of a pendulum.

Mechanical Energy

Derivation of Conservation of Mechanical Energy
Law of Conservation of Mechanical Energy: The total amount of mechanical energy, in a closed system in the absence of dissipative forces (e.g. friction, air resistance), remains constant. This means that potential energy can become kinetic energy, or vice versa, but energy cannot “disappear”.

Velocity of a Pendulum

The energy of a closed system is always conserved. This is an important law of physics! But energy does change forms. What are all the forms, how do they interchange, and how does this apply to things like free fall and pendulums

Velocity of a pendulum

What is the Law of Conservation of Energy

Law of Conservation of Energy: In an isolated system with no external forces applied to it, the total energy of the system must remain constant. Energy may change forms within the system but the total does not change.

In the case of a pendulum, energy cycles between potential and kinetic as the pendulum oscillates. When the end of the pendulum is momentarily at rest at its maximum height, there is no kinetic energy therefore all energy is in the form of potential energy. When the pendulum is at its minimum height, there is no potential energy therefore all energy is in the form of kinetic energy. Since the total amount of energy in the pendulum system must remain constant, the potential energy at the maximum height is equal to the kinetic energy at the minimum height. 


Physics Books

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Tullow Centre Library, Brigidine College. 2022