Chapter 3,3 - Work, energy and power Flashcards
1
Q
Work Done
A
The product of the force and the distance moved in the direction of the force
2
Q
Conservation of energy
A
The total energy in a closed system remains constant. Energy cannot be created or destroyed, it can only be transformed from one form to another
3
Q
Closed System
A
A system in which all energy transfers are accounted for. Energy or matter cannot enter or leave the system
4
Q
How work done is related to energy
A
Transfer of energy is equal to work done
5
Q
How to derive formula for kinetic energy
A
work done -> F=ma -> SUVAT E = Fd E = mad ad = E/m ad = (1/2)(v^2-u^2) (From SUVAT) consider u = 0 ad = (1/2)v^2 mad = (1/2)mv^2 E = (1/2)mv^2
6
Q
How to derive formula for gravitational potential energy
A
E = Fd E = mad E = mgh (different letters)
7
Q
Power
A
Work done per second
8
Q
Power in terms of force
A
P=Fv
9
Q
Efficiency of a system
A
useful energy / total input energy
