P1:Energy

Question 1

what is a system

Answer 1

object or group of objects

Question 2

what is the equation to find kenetic energy (J)

Answer 2

0.5 x mass(kg) x (speed,m/s)^2

Question 3

what is the equation for elastic potential (J)

Answer 3

0.5 x spring constant(n/m) x (extension,m)^2

Question 4

What is gravitational potential energy (J)

Answer 4

mass (kg)x gravitational field strength (n/kg) x height (m)

Question 5

How to calculate a change in thermal energy (j)

Answer 5

mass (kg) x specific heat capacity (j/kg celsius) x temperature (celsius)

Question 6

what is the required practical to test for specific heat capacity

Answer 6

1:place the beaker on top of balance and set it to zero
2:add oil to beaker and record the mass
3:put thermometer and immersion heater into the oil
4:read starting temperature and insulating foam
5:connect joulmeter to the immersion heater and connect power back to joulmeter
6:leave it for 30 min
7:read the total number of joules that pass through the immersion heater and read the final oil temperature

Question 7

why might there be inaccuracies in the test for specific heat capacity

Answer 7

thermal energy passes out of the beaker, not all thermal energy passes into the oil, incorrect reading, thermal energy not being spread out

Question 8

what are the 2 equations to find power (w)

Answer 8

energy transferred/time

work done(j)/time

Question 9

what can energy only do

Answer 9

store or dissipated

Question 10

what are the 2 equations for efficiency

Answer 10

useful output energy transfer/total input energy transfer

useful power output/total power input

Question 11

how can we increase efficiency

Answer 11

insulation lubrication and streamlining

Question 12

what is lubrication

Answer 12

a substance that reduces friction

Question 13

what is streamlining

Answer 13

an object shaped to travel through air and water with little resistance

Question 14

what is a renewable energy source

Answer 14

a resource that is being replenished as its used

Question 15

what are the main sources of energy

Answer 15

fossil fuels, nuclear fuels, biofuels, hydroelectricity,geothermal , the tides, the sun, and water wave

Question 16

name 3 ways of improving insulation

Answer 16

cavity walls(fills air space with material to stop heat loss)
double glazing,(air gap allows for insulation)
curtains (reduces amount of air exchange between cold window and room)
loft insulation(traps heat before it escapes through the roof of the home)