Work, Energy and Power Flashcards
Law of conservation of energy
Energy cannot appear or disappear in a closed system it must always take another form.
Work
Work is the method of transferring energy from one system to another.
Formula for work done, when the force and distance are parallel.
Work = Force x Distance
Formula for work done, when the force acts at an angle.
Work = Force x Distance x cos(Angle)
Kinetic energy
Kinetic energy is the energy that a body possesses by the virtue of being in motion.
Kinetic energy formula
K.E = 1/2 x Mass x Velocity^2
The work-energy theorem
Total work done = Change in kinetic ennergy
Potential energy
Potential energy arises from the position of an object.
Work done by gravity
- mgh
- Mass x Gravity x Height
Mechanical energy
It is the sum of an object’s kinetic and potential energy.
Mechanical energy formula
E = K + U
Mechanical energy = kinetic energy + potential energy
Conservation of mechanical energy
If no dissipative forces are acting on the system then the initial mechanical energy is equal to the final mechanical energy.
ki + ui = kf + uf
Conservation of mechanical energy with dissipative forces.
ki + ui + w = kf + uf
Power
The rate at which work gets done. Power is measured in watts.
Power formula (parallel)
Power = Work/Time Power = Force x Velocity
