5 : Work, energy and power Flashcards
1
Q
work done
A
- J
- the force required moving an object through a distance
- amount of energy transferred
- kinetic energy when moving
2
Q
power
A
- rate of energy transfer
- J s^ -1
- P= W/t
3
Q
power and motion
A
- a constant force is required to maintain a constant speed
- car ex - rate of work done by the forward provided by car engine is equal to the rate of work done against frictional forces
- P = Fv as v= x/t
4
Q
Efficiency
A
- ratio of useul energy outout to totel energuy input
5
Q
principle of energy onservation
A
- energy cannot be created nor destroyed
- total energy of a closed system remains constant
6
Q
loss of energy
A
- when energy is converted into a different form some is lost
- lost in sound or heat
- due to friction
7
Q
kinetic energy
A
- energy due to motion of an object with mass
- 1/2 mv^ 2
8
Q
gravitational potential energy
A
- energy of an object due to its position in a gravitational field
- mgh
- gained whrn an objectgets higher
9
Q
elastic potential energy
A
- energy stored in an object as a result of reversible change in its shape
- squashed spring
10
Q
chemical energy
A
- energy contained within the chemical bonds between atoms
- released when atoms are rearranged
energy stored in chemical cell
11
Q
electrical potential energy
A
- energy of electrical charges due to their position in an electric field
- static charge on ballons
12
Q
nuclear energy
A
- energy within the nuclei of atoms
- released when particles within the nucleus are rearranged
- energy from nuclear fission
13
Q
electromagnetic energy
A
- energy associated with EM waves
- stored with in the oscillating electric and magnetic fields
- an LED
14
Q
sound energy
A
- energy of mechanical waves due to the movement of atoms
15
Q
Internal energy
A
- the sum of random potential and kinetic energies of atoms in a system
