Good afternoon,

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New teacher here. Today I'm doing a demonstration on Newton's Second Law where we show with a meter stick and 2 balls of the same size but different mass how the mass of an object (with the applied force being the same from the meter stick) affects the object's acceleration. So I'm teaching the knowledge that's stated in their textbook (the object with a greater mass will have a lower acceleration) when I receive a question: "Why do objects with different masses hit the ground at the same time (we're talking a foam ball and tennis ball) when mass affects their acceleration in the demonstration?" I said I would explain tomorrow but I honestly don't know and haven't found the answer on the internet. Does anyone happen to know? Thank you to anyone who can provide knowledge on this!