Answer:
Coins made of a good conductor will slow down as they roll past the magnet.
Step-by-step explanation:
Conduction involves the transfer of electric charge or thermal energy due to the movement of particles. When the conduction relates to electric charge, it is known as electrical conduction while when it relates to thermal energy, it is known as heat conduction.
One of the ways in which a coin operated vending machine checks to make sure that the coins fed to it are genuine is to roll them past a strong magnet. As such, coins made of a good conductor will slow down as they roll past the magnet due to the force of attraction that exists between the magnet and the coin (metal).
This ultimately implies that, the magnet tends to attract the coin to itself and as such slowing down the motion of the coin. Similarly, if it's a fake coin, it simply means it would be a bad conductor and as such it will roll fast past the strong magnet.