Dynamics - Energy T9 Flashcards
1
Q
Work done
A
E(w) = fd
Energy = force x distance.
Energy is in joules (J), force in Newton’s (N) and distance in metres (m).
2
Q
Potential energy
A
E(p) = mgh
Energy in joules = mass (kg) x gravitational field strength (ms-2) x height (m)
3
Q
Power
A
P= E/T
Power in watts (w) equals Energy (J) divided by time (s)
4
Q
Kinetic energy
A
E(k) = 0.5mv2
Energy (J) = Half x mass (kg) x velocity squared (ms-1)
5
Q
Conservation of energy
A
Energy cannot be destroyed or created. It is always conserved. Total energy (J) before = Total energy (J) after.
6
Q
Wasted Energy
A
Sometimes energy is converted to a wasted for example a lightbulb heating up.
7
Q
Energy Efficiency calculations.
A
Efficiency (%) = (useful energy out / useful energy in) x 100.
