Course: Combined and Separate | Use g = 9.8 N/kg. Find each scene on YouTube, watch it, then answer the questions. Write your answers on paper first, then tap Show answer.
Equations you’ll need: GPE = mgh · KE = ½mv² · elastic PE = ½ke² · E = Pt · P = W ÷ t · efficiency = useful output ÷ total input
1. Up – the house takes off
🎬 The scene: Carl’s house lifts off from the city, carried by thousands of balloons.
Q1 (F) Which energy store of the house increases as it rises?
Show answer
Its gravitational potential energy store.
Q2 (F/H) A real house has a mass of about 50 000 kg. Calculate the GPE it gains rising 100 m.
Show answer
GPE = mgh = 50 000 × 9.8 × 100 = 49 000 000 J (49 MJ)
Q3 (H) Real or fake? A party balloon can lift about 10 g (0.01 kg). How many balloons would lift a 50 000 kg house? The film shows about 10 000 to 20 000.
Show answer
50 000 ÷ 0.01 = 5 000 000 balloons – hundreds of times more than in the film. Fake! (Some estimates are even higher.)
2. Home Alone – the swinging paint cans
🎬 The scene: Kevin swings paint cans on ropes down the stairs at the burglars. (Slapstick – the real cans were rubber.)
Q1 (F) Describe the energy transfer as a paint can swings down on its rope.
Show answer
Energy is transferred from the can’s gravitational potential store to its kinetic store.
Q2 (F/H) A 4 kg can drops through a height of 1.25 m as it swings. Calculate the GPE it loses.
Show answer
GPE = 4 × 9.8 × 1.25 = 49 J
Q3 (H) Assume all this GPE becomes kinetic energy. Calculate the can’s speed at the bottom of the swing.
Show answer
49 = ½ × 4 × v², so v² = 24.5 and v = 4.9 m/s. (In the film the cans were rubber – a real full can would cause serious injury!)
3. WALL-E – solar charging in the morning
🎬 The scene: WALL-E wakes up sluggish and opens his solar panels to recharge in the sunlight.
Q1 (F) WALL-E charges his battery using sunlight. Which energy store increases in the battery?
Show answer
The chemical energy store. (Energy is transferred by light, then electrically, to the battery’s chemical store.)
Q2 (F/H) His solar panel gives 50 W for 3 hours. Calculate the energy transferred.
Show answer
t = 3 × 3600 = 10 800 s. E = Pt = 50 × 10 800 = 540 000 J
Q3 (F/H) 250 W of sunlight hits the panel and it outputs 50 W. Calculate its efficiency. Give one disadvantage of relying on solar power.
Show answer
50 ÷ 250 = 0.2 = 20%. Disadvantage: it doesn’t work at night and gives less power when it is cloudy, so it is unreliable.
4. Toy Story – “falling with style”
🎬 The scene: Buzz jumps off the bed to prove he can fly, bouncing and swinging around Andy’s room. Woody: “That’s not flying, that’s falling with style!”
Q1 (F) When Buzz bounces off the ball, which energy store is briefly filled as the ball squashes?
Show answer
The ball’s elastic potential energy store.
Q2 (F/H) Buzz has a mass of 0.3 kg and falls 1.5 m. Calculate the GPE he loses.
Show answer
GPE = 0.3 × 9.8 × 1.5 = 4.41 J
Q3 (H) Ignoring air resistance, calculate his speed after falling 1.5 m. Woody says it isn’t flying – use energy to explain why he’s right.
Show answer
4.41 = ½ × 0.3 × v², so v² = 29.4 and v = 5.4 m/s. Buzz has no engine to transfer energy to him, so he can’t gain height – all his kinetic energy comes from losing GPE. That’s falling, not flying!
5. Kung Fu Panda – Po climbs the stairs
🎬 The scene: Po struggles up the thousands of steps to the Jade Palace, exhausted.
Q1 (F) As Po climbs, energy is transferred from which store to which store?
Show answer
From his chemical store (food) to his gravitational potential store – with some wasted heating him and the surroundings.
Q2 (F/H) Po has a mass of 120 kg and climbs 150 m. Calculate the work he does against gravity.
Show answer
Work done = GPE gained = 120 × 9.8 × 150 = 176 400 J
Q3 (H) The climb takes him 30 minutes. Calculate his useful power. Why does he need far more energy from food than this?
Show answer
t = 30 × 60 = 1800 s. P = 176 400 ÷ 1800 = 98 W. The body is inefficient – most energy from food is wasted heating the body and surroundings (that’s why he gets hot and sweaty).
6. Big Hero 6 – Baymax on low battery
🎬 The scene: Baymax’s battery runs low and he wobbles around like he’s half asleep until Hiro gets him home to recharge.
Q1 (F) What energy store in Baymax is running low?
Show answer
The chemical energy store of his battery.
Q2 (F/H) His charger supplies 200 W for 2 hours. Calculate the energy transferred.
Show answer
t = 2 × 3600 = 7200 s. E = 200 × 7200 = 1 440 000 J
Q3 (F/H) Chargers and batteries get warm while charging. What does this tell you about the efficiency of charging?
Show answer
Some energy is wasted heating the charger, battery and surroundings, so charging is less than 100% efficient – less than 1 440 000 J ends up in the chemical store.
7. Monsters, Inc. – switching to laugh power
🎬 The scene: At the end of the film, Monsters, Inc. switches from collecting screams to collecting laughter – which turns out to be ten times more powerful.
Q1 (F) Monstropolis switches from screams to laughter for its energy. Which real-life change is this most like?
Show answer
Switching from a resource that is running out (like fossil fuels) to a better, cleaner one (like renewables).
Q2 (F/H) Laughter is “ten times more powerful”. If a scream gives 500 J, how many screams or laughs are needed to supply 1 000 000 J?
Show answer
Screams: 1 000 000 ÷ 500 = 2000. A laugh gives 5000 J, so laughs: 1 000 000 ÷ 5000 = 200.
Q3 (H) Give two things you would compare when deciding which real energy resource a country should use.
Show answer
Any two: reliability, whether it is renewable, environmental impact (e.g. CO₂ emissions), cost to build and run, how much energy it can supply.
8. The Angry Birds Movie – the giant slingshot
🎬 The scene: The pigs show off their giant slingshot by launching Red through the air.
Q1 (F) Describe the energy transfers from pulling back the slingshot to Red flying upwards.
Show answer
Elastic potential (stretched band) → kinetic (Red moving) → gravitational potential (as he rises).
Q2 (F/H) The band has a spring constant of 500 N/m and is stretched by 2 m. Calculate the elastic potential energy stored.
Show answer
Ee = ½ke² = ½ × 500 × 2² = 1000 J
Q3 (H) Red has a mass of 2 kg. Assuming all 1000 J becomes kinetic energy, calculate his launch speed.
Show answer
1000 = ½ × 2 × v², so v² = 1000 and v = 32 m/s (to 2 s.f.). In reality it would be less, because some energy is wasted heating the band and the air.
9. Happy Feet – sliding down the ice
🎬 The scene: Mumble and his friends belly-slide at speed down an icy slope.
Q1 (F) Why can the penguins slide so fast on ice?
Show answer
Ice is smooth, so there is very little friction. Less energy is wasted heating the ice, so more GPE becomes kinetic energy.
Q2 (F/H) A 20 kg penguin slides down a slope 20 m high. Calculate the GPE it loses.
Show answer
GPE = 20 × 9.8 × 20 = 3920 J
Q3 (H) Ignoring friction, calculate its speed at the bottom. Does the mass of the penguin matter?
Show answer
3920 = ½ × 20 × v², so v² = 392 and v = 20 m/s (to 2 s.f.). Mass doesn’t matter: mgh = ½mv², so the m cancels and v² = 2gh for any penguin.
10. Cool Runnings – the bobsleigh crash
🎬 The scene: On their final run, the Jamaican team’s bobsleigh flips and crashes – and they carry it over the finish line.
Q1 (F) At the start, the team push the bobsleigh. Which energy store do they increase?
Show answer
The bobsleigh’s kinetic energy store. They do work on it.
Q2 (F/H) The bobsleigh and crew have a mass of 630 kg and travel at 35 m/s. Calculate their kinetic energy.
Show answer
KE = ½ × 630 × 35² = ½ × 630 × 1225 = 385 875 J (about 390 000 J)
Q3 (H) When they crash, the bobsleigh stops. Where does all its kinetic energy go?
Show answer
It is transferred to the thermal stores of the bobsleigh, ice and surroundings (by friction), by sound, and into damaging (deforming) the bobsleigh. The energy is not destroyed – it is dissipated.
Teachers: the buttons open a YouTube search, so you can pick whichever upload is currently available. Please watch the clip through before showing it to a class.
