Energy Transformations

Question 1

What are the types of potential energies?

Answer 1

Chemical: the energy stored in chemical bonds and structural arrangement of atoms or molecules
Nuclear: energy of the particles inside the nucleus released in nuclear reactions
Gravitational: energy an object possesses due to its position above some reference level
Elastic: energy possessed by an elastic material that has been stretched or compressed

Question 2

What are the types of kinetic energies?

Answer 2

Electrical: energy possessed by the moving of electrons through a conductor
Sound: energy transferred between molecules by vibrations
Thermal: energy an object has as a result of random motion of its molecules
Radiant: Energy that travels as electromagnetic waves (light, UV and radio waves)

Question 3

Whats the difference between renewable and non-renewable energy?

Answer 3

Renewable energy is any energy that can renew itself within the span of a human lifetime.

Question 4

What are the effects on gravitational potential energy?

Answer 4

Mass: more mass = more GPE
Height: more height = more GPE
Gravitational Field: more intense the gravitational field = more GPE

Question 5

Whats the formula for gravitational potential energy?

Answer 5

GPE = mgh
m = mass in grams
g = gravity (9.8 usually)
h = height in metres (m)

Question 6

What are the effects on kinetic energy?

Answer 6

Mass increases KE

Speed increases KE more than mass

Question 7

What is the formula for kinetic energy?

Answer 7

KE = (1/2)mv^2

Question 8

What is the work-energy theorem?

Answer 8

work = ∆E (energy) = E (final) - E (initial)

Question 9

What is the formula for thermal energy?

Answer 9

E = F (friction) * ∆d
F is the force of friction
∆d is displacement
Work done by friction is equal to the amount of energy transferred from mechanical energy to thermal energy

Question 10

Whats the law of conservation of energy

Answer 10

Energy cannot be created or destroyed, only transformed

Question 11

How is power calculated?

Answer 11

Power is the rate at which work is done or energy is transformed
P = W/∆t = ∆E/∆t
∆E is the amount of energy transformed
∆t is the time that passed

Question 12

How is efficiency calculated?

Answer 12

The ratio of useful energy output to energy input
Efficiency = E (output) / E (input) = P (output) / P (input)
% efficiency = efficiency * 100