QUESTIONSHEET 1

(a) work done = force ´ distance moved 1 1

50 ´ 10 ´ 2.5 1 1

= 1250 J/Joules 1 1

(b) (i) Mike 1750 1 1

Jeff 1500 1 1

(ii) Jeff 1 1

(iii) Mike 1 1

(c) force = work done

distance moved 1 1

1750 / 2 = 875N 1 1

875 / 10 1 1

87.5 kg 1 1

(Marks will be awarded for the calculation even if the work done by Mike was wrongly calculated in b(i))

TOTAL / 11

QUESTIONSHEET 2

(a) work done = force ´ distance moved 1 1

650 ´ 500 1 1 = 325 kJ/325,000 J 1

= 325 KJ/ 325,000 J 1

(b) 500 ´ 500 = 25 000 J 1 1

250 000 / 2000 1 1

= 125 W/watts 1 1

(c) 650 ´ 500 = 325 000 J 1 1

325 000 / 5000 1 1

= 65 W/watts 1 1

125 – 65 = 60 W/watts 1 1

Note: Do not deduct further marks if incorrect answer from b) is used correctly in subsequent calculations.

TOTAL / 10

QUESTIONSHEET 3

(a) (i) converted to/becomes/changes to kinetic energy. 1

(ii) 1 x 45 1 1

= 45 kJ/45,000 J 1 1

(b) velocity = 1

1000 / 10 = 100 kg 1

v = 1

= 30 ms^-1 1 1

(c) work done = gain in potential energy 1 1

= 45 kJ/45,000 J 1 1

TOTAL / 9

QUESTIONSHEET 4

(a) 120 ´ 10 1 1

= 1200 J/1.2 kJ 1 1

(b) 120 ´ 5 1 1

= 600 J 1 1

(c) (i) 600 ´ 100 1

1200

= 50% 1 1

(ii) friction in wheels 1 1

(iii) oil wheels 1 1

TOTAL / 8

QUESTIONSHEET 5

(a) energy efficient bulb: 20 / 21 ´ 100 1 1

= 95% 1 1

standard bulb: 100 / 180 ´ 100 1 1

= 20% 1 1

fluorescent strip: 20 / 28 ´ 100 1 1

= 60% 1 1

(b) (i) standard bulb 1 1

(ii) lost as heat 1 1

(c) use less electricity for the same light output 1 1

last longer so less resources used in a given time 1

TOTAL / 10

QUESTIONSHEET 6

(a) KE = ½ m v² 1 1

= ½ ´ 5000 ´ 3² 1 1

= 22500 J 1 1

(b) 3 / 5 1 1

= 0.6 m/s 1 1

(c) ½ ´ 25 000 ´ 0.6² 1 1

= 4500 J 1 1

(d) (i) 22 500 - 4 500 = 18 000 J 1 1

(ii) converted to heat 1 1

and sound 1 1

TOTAL / 10

QUESTIONSHEET 7

(a) Watts 1 1

(b) one Watt = one Joule per second 1 1

(c) energy = force ´ distance 1 1

= 80 ´ 10 ´ 30 1 1

= 24 000 J 1 1

(d) Power = energy / time 1 1

= 24 000 / 15 1 1

= 1600 W or 1.6 kW 1 1

TOTAL / 8

QUESTIONSHEET 8

(a) 55 ´ 10 = 550 N 1 1

(b) (i) energy = force ´ distance 1 1

= 3.5 ´ 550 1 1

= 1925 J 1 1

(ii) 1925 J 1 1

(c) v² = u² + 2as 1 1

0 = 12² + 2 ´ -10 x s 1 1

s = 144 / 20 1 1

= 7.2 m 1 1

(d) 900 / 3 1 1

= 300 W 1 1

TOTAL / 11

QUESTIONSHEET 9

(a) (i) 30 ´ 10 ´ 3 1 1

= 900 J/joules 1 1

(b) 900 J/joules 1 1

(c) (1) muscles of the man/food man has eaten/

chemical energy in food 1 1

(2) lift motor 1 1

TOTAL / 5

QUESTIONSHEET 10

(a) (i) 600 kJ/600,000 J 1 1

(ii) 3.6 MJ/3,600 kJ 1 1

(b) energy of light bulb = 1 500 000 W 1 1

time = energy transferred / power 1 1

4 h 10 min/250 min 1 1

(c) (i) electrical to heat energy 1 1

(ii) electrical to heat and light energy 1 1

(iii) electrical to heat and movement/kinetic energy 1

TOTAL / 8

QUESTIONSHEET 11

(a) (i) potential energy to kinetic energy 1 1

(ii) kinetic energy to sound and kinetic energy 1 1

(iii) kinetic energy to potential energy 1 1

(b) (i) 300 / 1000 ´ 10 1 1

= 0.3 ´ 1.8 1 1

= 0.54 J 1 1

(ii) potential energy has become kinetic energy at the instant

it hits the ground 1 1 = SQRT (o.54 / 0.5 x 0.3) 1

= 1

= 6 ms^-1 1 1

TOTAL / 9

QUESTIONSHEET 12

(a) using work done = force ´ distance moved 1 1

430 ´ 4/4 = 430 W (Lucy) 1 1

450 ´ 4/6 = 300 W (Carol) 1 1

(b) Lucy 1 1

(c) her muscles 1 1

(d) Carol 1 1

She would do the most work as she was the heaviest/ had greatest weight 1 1

TOTAL / 7

QUESTIONSHEET 13

(a) supplied as part of nature/generated in a way that the Earth’s resources not used up. 1 1

(b) (i) 200 1 1

(ii) Wind does not blow all the time. 1 1

(c) (i) rearranging equation 1 1

5 ´ 3300 ´ 60 1 1

= 990,000 M J 1 1

(ii) 495,000 MJ 1 1

TOTAL / 7

QUESTIONSHEET 14

(a) Joule 1 1

(b) (i) energy = force ´ distance 1 1

0.3 ´ 10 ´ 0.5 1 1

1.5 J 1 1

(ii) 1.5 J 1 1

(iii) 0.3 ´ 10 1 1

3 N 1 1

TOTAL / 7

QUESTIONSHEET 15

(a) (i) No loss of kinetic energy 1 1

(ii) lose energy as heat 1 1

and sound 1 1

(b) (Two from)

air bag - absorbs kinetic energy of driver

crumple zone – absorbs KE of car

seat belt – exerts force to stop driver 4 4

(c) (i) KE = ½ m v² 1 1

= ½ ´ 2000 ´ 15² 1 1

= 225 000 J or 225 kJ 1 1

(ii) Force = energy / distance 1 1

= 225 000 / 30 1 1

= 7500 N 1 1

TOTAL / 13

QUESTIONSHEET 16

(a) (i) chemical 1 1

à electrical 1 1

à kinetic 1 1

(ii) work done = force x distance 1 1

= 3 ´ 1 = 3 J 1 1

(iii) Power = energy / time 1 1

= 3 / 10 = 0.3 W 1 1

(b) (i) potential 1 1

à kinetic 1 1

à electrical 1 1

à heat & light 2 2

(ii) KE = ½ m v² 1 1

= ½ ´ 1 ´ 2² 1 1 = 2 J 1

(c) chemical 1 1

à heat 1 1

à kinetic 1 1

TOTAL / 17

QUESTIONSHEET 17

(a) heat and light (either order) 2 2

(b) chemical 1 1

sound 1 1

(c) kinetic and sound (either order) 2 2

(d) heat and light (either order) 2 2

TOTAL / 8

QUESTIONSHEET 18

(a) Six from

kinetic, potential, electrical, heat, light, sound,

chemical, nuclear 6 6

(b) (i) Newton 1 1

metre 1 1

(ii) conservation 1 1

changed 1 1

created 1 1

destroyed 1 1

TOTAL / 12

QUESTIONSHEET 19

(a) too much emphasis on nuclear energy 1 1

not enough spent on renewable sources 1 1

(b) secondary source of energy 1 1

made from the others 1 1

(c) gas 1 1

oil 1 1

TOTAL / 6

QUESTIONSHEET 20

(a) (i) the sun 1 1

(ii) photosynthesis 1 1

produces glucose / sugar which stores energy 1 1 converted to storable form 1

(iii) plants die 1 1

subjected to high temperatures and pressures 1 1

over millions of years 1 1

(b) (i) A 1 1

(ii) C 1 1

TOTAL / 8