Thanks, Zappy for your advice. I came across the following wuestion:
A 50-kg wooden crate of 1 m height, 1 m length and 1 m breadth was placed on a cart. The cart was pulled around a bend at a high speed without toppling. Another wooden crate of the same size and weight was placed on top of the first crate. The cart was pulled at the same speed around a bend. This time, the cart and its two crates overturned.
A double decker bus has 50 seats on the lower deck and 30 seats on the upper deck. If all the seats were taken up, passengers would be allowed to stand. The bus rule states that standing passengers are allowed only on the lower deck.
Question: why are standing passengers not allowed on the upper deck?
Which primary school topic is tested here? How to answer this?