Understanding Energy: Types, Transformations, and Efficiency

What is the formula for Gravitational Potential Energy (GPE)?

GPE = mgh

where m is mass (kg), g is acceleration due to gravity (9.8 m/s²), and h is height (m).

What is Kinetic Energy (KE) and how is it calculated?

Kinetic Energy is the energy of an object in motion

KE = 1/2 mv²

where m is mass (kg) and v is velocity (m/s).

What is the Law of Conservation of Energy?

energy cannot be created or destroyed, only converted from one form to another.

What is energy efficiency?

a measure of how much input energy is converted into useful output energy,

often expressed as a percentage.

How do you calculate the efficiency of a device?

Efficiency = (Useful Energy Output / Total Energy Input) x 100%.

Convert 10 kJ to Joules using Scientific Notation.

10 kJ = 1.0 x 10^4 J.

How do you convert 3.2 Mm to meters?

3.2 Mm = 3.2 x 10^6 m.

How do you convert 2.5 mm to meters?

2.5 mm = 2.5 x 10^-3 m.

How do you convert 3.0 μm to meters?

3.0 μm = 3.0 x 10^-6 m.

How do you convert 10 nm to meters?

10 nm = 1.0 x 10^-8 m.

What is the gravitational potential energy equation of a 3kg cat sitting on a 2m fence?

GPE = 3kg 9.8 m/s² 2m = 58.8 J.

What is the kinetic energy formula of a 4.5kg bowling ball traveling at 32 m/s?

KE = 1/2 4.5kg (32 m/s)² = 2304 J.

What is the gravitational potential energy formula of a 450g soccer ball at the top of a 9m height?

GPE = 0.45kg 9.8 m/s² 9m = 39.24 J.

What is the kinetic energy formula of a 450g soccer ball with a velocity of 13 m/s?

KE = 1/2 0.45kg (13 m/s)² = 38.25 J.

What is mechanical energy (ME)?

sum of kinetic energy and gravitational potential energy

(ME = KE + GPE).

What is the input energy if a kettle inputs 1000kJ of electrical energy?

output thermal energy should also be 1000kJ, assuming no energy loss.

What is the useful energy and wasted energy in a light bulb that consumes 200J of electrical energy but emits 25J of light energy?

Useful energy = 25J (light), Wasted energy = 200J - 25J = 175J.

How much thermal energy does a wind turbine waste if it transforms 1,500,000J of mechanical energy into 1,000,000J of electrical energy?

Thermal energy wasted = 1,500,000J - 1,000,000J = 500,000J.

How much useful mechanical energy does an engine transform if it transforms 7,000J of chemical energy and wastes 5,000J as thermal energy?

Useful mechanical energy = 7,000J - 5,000J = 2,000J.

What is the efficiency of the engine that transforms 7,000J of chemical energy and wastes 5,000J?

Efficiency = (2,000J / 7,000J) x 100% = 28.57%.

What types of energy are stored as potential energy?

Stored energy types include elastic potential energy, gravitational potential energy, chemical energy, and nuclear energy.

What types of energy are considered kinetic energy?

Kinetic energy types include light, electrical, sound, heat, and kinetic energy.

What happens to GPE if the height of an object is doubled?

If the height is doubled, the GPE also doubles.

What happens to KE if the velocity of an object is doubled?

If the velocity is doubled, the KE increases by a factor of four (since KE is proportional to the square of velocity).