A pencil falls from a table 80 cm high, and time it falls.

Problem data: h (height of the table from which the pencil fell) = 80 cm (in SI h = 0.8 m).

Reference values: g (acceleration due to gravity) ≈ 10 m / s2.

Let us express the time when the pencil falls from the table from the formula: S = h = g * t2 / 2, whence t = √ (2h / g).

Let’s perform the calculation: t = √ (2 * 0.8 / 10) = 0.4 s.

Answer: The time for the pencil to fall off the table is 0.4 s.