Formulas & tables/Physics/Kinematics/Fall time in horizontal projectile motion

Fall time in horizontal projectile motion

t=\sqrt{\dfrac{2h}{g}}

Result unit: s (second)

What it describes

The fall time in horizontal projectile motion depends only on the height — just like in free fall.

t

fall time

[s]

h

height

[m]

g

gravitational acceleration

[m/s²]

In horizontal projectile motion the vertical motion is independent of the horizontal one — vertically it is free fall. From

h=\tfrac12 g t^2

it follows that

t=\sqrt{2h/g}

, so the time depends only on the height, not on

v_0

Horizontal projectile motion (initial velocity directed horizontally). A body simply dropped from the same height takes the same time.

How long does a body thrown horizontally from a height of 20 m take to fall?

Substitution

h=20

g=10

m/s².

Result

t=\sqrt{\dfrac{2\cdot20}{10}}=2

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