chapter 1 -conservation and dissipation of energy

Question 1

what are 3 examples of energy stores?

Answer 1

any from

gravitational 
kinetic 
chemical 
electrical
thermal
sound
light 
elastic 
nuclear

Question 2

how does a firework transfer energy?

Answer 2

Thermal energy >
chemical energy >
releases:
light 
sound
kinetic
thermal energy

Question 3

why is repeating measurements better than just taking one measurement in an experiment?

Answer 3

because it ensures more accurate evidence and results.

Question 4

what is the equation for energy transfer?

Answer 4

work done = force x distance

Question 5

what is the equation to work out the amount of kinetic energy there is?

Answer 5

ke = 0.5 x M x (V x V)

ke - kinetic energy
M - mass
V - velocity

Question 6

what is the equation to work out the gravitational potential energy?

Answer 6

GPE= M x G x H

GPE = Mass x Gravitational field strength x height.

Question 7

what does efficiency mean?

Answer 7

Good at transferring energy and not much energy is wasted.

Question 8

what is the equation for any device that transfers energy?

Answer 8

efficiency = useful output energy transferred by the device / total input energy supplied to the device (x100 for percentage)

Question 9

what is one example of a biofuel?

Answer 9

wood

Question 10

name the process in which nuclear fuel provides the energy needed to generate electricity?

Answer 10

nuclear fusion

Question 11

what happens to any energy that is not usefully transferred into solar cells?

Answer 11

it goes into the atmosphere

Question 12

what is one advantage of aircrafts having fuel cells as well as the solar cells?

Answer 12

they waste less energy and therefore are more efficient and so they can fly at night and don’t need sun light to run.

Question 13

what is one environmental advantage of using electrical motors to drive aircraft propellers rather than motors that burn a fuel?

Answer 13

It doesn’t use up so much Co2