Physics and maths tutor Energy flashcards

Question 1

Equation for kinetic energy

Answer 1

1/2mv^2
1/2 x mass x velocity^2
energy(J),mass(kg),velocity(m/s)

Question 2

Equation for elastic potential energy

Answer 2

1/2kx^2
1/2 x spring constant x extension^2
energy(J),spring constant(N/m),extension(m)

Question 3

Equation for gravitational potential energy

Answer 3

mgh
mass x gravitational field strength height
energy(J),mass(kg),gravitational field strength(N/kg),height(m)

Question 4

Specific heat capacity

Answer 4

the amount of energy needed to raise the temperature of 1 kilogram of a substance by 1 degree Celcius

Question 5

Units for specific heat capacity

Answer 5

J/degreeC/kg

Question 6

define power

Answer 6

the rate at which energy is transferred or rate at which work is done

Question 7

give two equations for power

Answer 7

power= energy trasferred/time
power=work done/time
Energy(J),work done(J), time(s)

Question 8

What is the unit of power?

Answer 8

Watt(W)

Question 9

Give some examples of chemical energy stores

Answer 9

food, fuel (eg. wood, coal, petrol), batteries

Question 10

State four different stores of energy

Answer 10

kinetic energy, gravitational potential energy, elastic potential energy,chemical energy

Question 11

two equations for efficiency

Answer 11

efficiency=useful energy output/ total energy input

efficiency=useful power output/ total power input

Question 12

the equation for change in thermal energy

Answer 12

change in thermal energy= mass x specific heat capacity x temperature change