Work, Energy, and Power Flashcards
Define work
Work is the product of force and distance
W = FS
W = FS cos θ
Unit is joules
Define energy
Energy is the ability to do work. The s.i unit is joules
Sources of energy
Renewable and Non Renewable
Define renewable
These are formed or replaced by natural processes and the forces are persistent in the natural environment
Examples of renewable
Solar energy
Wind energy
Biomass from plants
Hydropower from flowing water
Geothermal energy
Define Non-renewable
This is the natural resource that cannot be readily replaced by a natural means, most especially at a pace quick enough to keep up with consumption
Examples of Non-renewable energy
Carbon based fossils
Ground water
Earth minerals like metal ore, fossil fuels, coals, petroleum and natural gas
Forms of energy
Mechanical
Light
Chemical
Heat
Tidal
Magnetic
Types of mechanical energy
Potential and kinetic energy
Types of potential energy
Gravitational potential energy
P.E = mgh
elastic potential energy
P.E =1/2 KX²
Define elastic potential energy
This is the energy possessed by a body when stretched or compressed
P.E = 1/2 kx²
K - force constant
x - extension, change in length
Define gravitational potential energy
gravitational potential energy is the energy possessed by virtue of the position in gravitational field
Derive K.E mathematically
F = MA
V² = u² + 2as
2as = v² - u²
Divide both side by 2
As = (v² - u²) / 2
W = F x S > W = ma s
Since we know as input into W
W = m ((v² - u²) / 2)
U = 0
W = m ( v²- 0²) / 2
W = mv²/ 2
K.E = 1/2 mv²
