Why did the flat sheet of paper fall at the same rate as the book?

Answer 1

If that's what actually happened, then you must have done the experiment either

in a vacuum chamber or else on the moon, where there's no air.

When gravity is the only thing around, all objects fall with the same acceleration,

speed, and velocity, no matter what shape, size, or mass they have ... a feather

and a Bowling ball fall together. But when they have to fall through air, that's when

heavy things fall faster.

Answer 2

Both the flat sheet of paper and the book fall at the same rate because they experience the same gravitational pull from the Earth. In the absence of air resistance, all objects fall at the same rate regardless of their mass. This is known as the principle of universal gravitation.