alleryStart learning →A book rests on a desk and does not fall to the floor. Why?
AGravity does not act on books
BThe desk pushes up and balances gravity
CAir below the book holds it up
DFriction holds it against the desk
Answer & Solution
Correct answer: B. The desk pushes up and balances gravity
The desk surface pushes up on the book with a force equal to its weight, so the two forces cancel and the book stays still.
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