Unit 1 - Energy Flashcards
What is the law of conservation of energy?
Energy cannot be created or destroyed, only transformed from one form to another.
Why is some energy ‘lost’ during energy transformations?
Because not all energy is converted into useful forms; some is transformed into unwanted forms like heat or sound.
What is an example of wasted energy in a car engine?
Heat and sound energy.
What causes energy loss in braking a bicycle?
Frictional forces transform kinetic energy into heat energy in the brakes.
What is the formula for work done against friction?
Ew = F × d, where F is the frictional force and d is the distance.
What is kinetic energy?
The energy an object possesses due to its motion.
What is the formula for kinetic energy?
Ek = ½ × m × v²
What two factors does kinetic energy depend on?
Mass of the object and its speed.
What is gravitational potential energy?
Energy an object has due to its position above the Earth’s surface.
What is the formula for gravitational potential energy?
Ep = m × g × h
What is the gravitational field strength on Earth?
9.8 N/kg
What happens to energy when a mass is dropped from a height?
Gravitational potential energy is transformed into kinetic energy.
What happens to energy when an object is projected upwards?
Kinetic energy is transformed into gravitational potential energy.
What assumption is made when ignoring energy losses?
The transformation between kinetic and potential energy is 100% efficient.
