Physics - Mechanics

Falling Speed Explained Simply

If you simply let go of an object (without throwing it), gravity makes it go faster and faster as it falls. This is called free fall.

v = g · t v = speed after time t, g = gravitational acceleration ≈ 9.81 m/s²

So the falling speed increases steadily with time. Every additional second adds about 9.81 m/s of speed.

Example: speed

After t = 1 s: v = 9.81 · 1 = 9.81 m/s (about 35 km/h)

After t = 2 s: v = 9.81 · 2 = 19.62 m/s (about 71 km/h)

After t = 3 s: v = 9.81 · 3 = 29.43 m/s (about 106 km/h)

If you want to know how far something has fallen in that time (the fall distance), you need a second formula:

s = ½ · g · t² s = fall distance in meters

Example: fall distance

After t = 2 s: s = 0.5 · 9.81 · 2² = 0.5 · 9.81 · 4 = 19.62 m

So after 2 seconds of free fall, an object has already fallen almost 20 meters - and keeps getting faster.

💬 Mia asks Grandpa Theo

Mia

So do you keep getting faster and faster forever, if you fall long enough?

Grandpa Theo

Only in theory, without air! In reality, air resistance brakes you more and more over time, until the drag force and gravity balance out.

Mia

Ah, like skydiving, right?

Grandpa Theo

Exactly! That's called terminal velocity - pretty fast without a parachute, but thankfully much slower with one.

The way falling speed increases so steadily is directly connected to the law of conservation of energy: the potential energy from up high gets converted into kinetic energy bit by bit.

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