Experiment Day Pop Quiz

Experiment Day Pop Quiz

By Thomas Lai

​From February Experiment Day

​Mary saw a video online about a coin tower challenge. In order to succeed in this challenge, she would have to remove the bottom coin off a stack of coins using a ruler without causing the tower to fall. She prepared her setup as shown in Diagram A.

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​Mary used the ruler to swipe the bottom coin off the coin tower in one swift motion from left to right, as shown in Diagram B. She successfully managed to swipe away the bottom coin, as shown in Diagram C.

Multiple Choice

 Her teacher mentioned that there is a type of force, X, in between each coin in the coin tower. What could be force X?

• Frictional force

• Magnetic force

• Gravitational force

• Elastic spring force

Open Ended

Although Mary exerted a pushing force on the coin tower when she swiped the bottom coin with her ruler, the coin tower did not topple. Explain, in terms of forces, why the coin tower did not topple.