Energy Flashcards
How many stores of energy are there?
8
What are the 8 energy stores
.magnetic
.internal (thermal)
.chemical
.kinetic
.electrostatic
.elastic potential
.gravitational potential
.nuclear
What are the 4 types of energy transfer?
.mechanical work
.electrical work
.heating
.radiation
What’s the the law of conservation of energy
energy cant be created or destroyed - only converted from one form of energy to another
Examples of conservation of energy —-> Reveal answer to see
a skydiver jumps out of a plane, he begins to lose gravitational potential energy as his height decreases and he gains kinetic energy as his speed increases.
smartphones contain a battery that stores chemical energy. When a smartphone is used, electrical work is done and a current flows - the battery’s chemical energy is transferred in a number of ways to LIGHT the screen and produce SOUND.
How do you calculate the amount of kinetic energy in a moving object?
Kinetic energy = 1/2 X mass X speed2
Ek = 1/2 m v2
What is kinetic energy (Ek) measured in?
joules (J)
What is mass (m) measured in?
kilograms (kg)
What is speed (v) measured in?
metres per second (m/s)
An apple of mass 100 g falls from a tree. It reaches a speed of 6 m/s before landing on Isaac’s head. What is the gain of kinetic energy of the apple?
1.8 J
Solution
Ek = 1/2 m v2
Ek = 1/2 X 0.1 X 36
Ek = 1.8 J
What is elastic potential energy (Ee) measured in?
Joules (J)
What is elastic potential energy (Ee) measured in?
newtons per metre (N/m)
What is extension (e) measured in?
metres (m)
How do you calculate elastic potential energy?
elastic potential energy = 1/2 X spring constant X extension squared
Ee = 1/2 K e2
How do you calculate gravitational potential energy?
Gravitational potential energy = mass × gravitational field strength × height
Ep = m g h
