2. Energy Flashcards
What is the relationship between work done, force, and distance?
The relationship between work done, force, and distance is: Work done = Force × Distance.
What is the efficiency of a device?
Efficiency is the ratio of useful energy out to total energy in, expressed as a percentage.
What factors are considered when selecting fuels for different situations?
Factors such as ease of storage, energy content, and safety are considered when selecting fuels for different situations.
How is energy transferred when work is done against frictional forces?
When work is done against frictional forces, energy is transferred, usually in the form of heat.
What is meant by energy transfer, and how does it occur?
Energy transfer refers to the movement of energy from one place to another or from one form to another. It occurs when a system changes.
What is meant by the conservation of energy?
The conservation of energy states that energy cannot be created or destroyed; it can only be transferred or transformed from one form to another.
What are some examples of renewable energy sources, and why are they important?
Examples of renewable energy sources include wave power, solar power, and geothermal power.
They are important because they are sustainable and have minimal environmental impact compared to non-renewable sources like fossil fuels.
How is elastic potential energy calculated for a stretched spring?
Ee = ½ke²
What formula is used to calculate gravitational potential energy for an object raised vertically?
Ep = m×g×h,
What is the formula for kinetic energy of a moving object?
Ek = ½mv²
How is power related to work done or energy transferred over time?
P = W/t
What is an example of oscillating motion where energy is transferred between kinetic energy and gravitational potential energy?
A simple pendulum.
What happens when energy is transferred, and only part of it is used for its intended purpose?
When energy is transferred, only a portion of it may be usefully transferred, with the remainder being dissipated and stored in less useful forms. This phenomenon is often referred to as energy being ‘wasted’.
How is efficiency calculated?
(useful energy out/total energy in) × 100
