Elementary Physics quiz

More questions about Elementary Physics

These visible examples show the question style. LearnClash turns the full topic into ranked duels and spaced repetition.

1. 1 Easy

   Why does a helium balloon rise upward through the surrounding air?

   Answer: Lower density

   Why: The buoyant force exerted by the displaced heavier air exceeds the total weight of the helium balloon.

2. 2 Medium

   Why is the sky on the Moon always black?

   Answer: No atmosphere

   Why: The Moon is not quite airless, but its gas is a million billion times thinner than our air: far too little to scatter sunlight.

3. 3 Hard

   What unusual event can happen when you freeze very hot water?

   Answer: It freezes faster

   Why: Schoolboy Erasto Mpemba reported it in 1963 while making ice cream; careful lab repeats often fail, so physicists still debate the effect.

4. 4 Easy

   Which principle makes heavy and light objects fall at identical rates in a vacuum?

   Answer: Equal gravitational acceleration

   Why: Apollo 15 astronaut David Scott demonstrated this on the Moon by dropping a hammer and feather simultaneously.

5. 5 Medium

   What happens to your mass when you travel to the Moon?

   Answer: It stays the same

   Why: The Moon pulls about a sixth as hard as Earth, so a 70 kg astronaut carries the same matter but tips a lunar scale at roughly 12 kg.

6. 6 Hard

   What is the temperature of absolute zero measured in Celsius?

   Answer: -273.15°C

   Why: Nothing can ever quite reach it: the coldest known natural place, the Boomerang Nebula, still sits about one degree above.