Q: What is Terminal Velocity?
A: When a body falls freely in the air, from a height, it starts to accelerate because of gravity. At first, it falls faster and faster, but as its velocity increases, soon another force begins to act in the opposite direction — air resistance (drag). As the object speeds up, air resistance increases until it balances the downward pull of gravity. At this point, the object stops accelerating and continues to fall at a steady maximum speed.
This constant speed is called terminal velocity.
In simple terms:
Terminal velocity is the fastest speed a falling object can reach in a fluid (like air or water), where the force of gravity is equal to the force of air resistance.
For example, a human skydiver in a belly-to-earth position usually reaches a terminal velocity of around 200 km/h (about 55 m/s). If they dive headfirst, the streamlined body position reduces air resistance, and the terminal velocity can reach 320 km/h (about 90 m/s).
Factors Affecting Terminal Velocity
Several factors determine how fast an object’s terminal velocity will be. These are:
- Mass of the Object – Heavier objects generally have higher terminal velocity.
- Shape of the Object – A streamlined shape reduces drag, allowing it to fall faster.
- Surface Area – The larger the area facing the airflow, the greater the resistance (parachutes work on this principle).
- Density of the Fluid – Air, water, or oil all create different levels of resistance.
Do You Know?
- A raindrop doesn’t fall at lightning-fast speeds. Instead, its terminal velocity is around 8–10 m/s (about 36 km/h) — fast enough to feel but not to hurt you.
- In the vacuum of space, there is no air resistance. Without air resistance, there’s no terminal velocity. All objects, regardless of their weight, continue to accelerate until they hit the ground. That’s why a feather and a hammer fall at the same rate on the Moon, as shown by Apollo 15 astronaut David Scott. On Earth, air resistance makes all the difference!
- The highest recorded free-fall speed was set by Felix Baumgartner in 2012 during his stratospheric jump — he reached 1,357 km/h before slowing down!
FAQs About Terminal Velocity
Q1: Is terminal velocity the same for all objects?
No. It depends on mass, shape, surface area, and the fluid through which the object falls.
Q: Why Does a Falling Body Through Air Not Keep Accelerating?
A falling body doesn’t keep accelerating because, as its speed increases, air resistance (drag) also increases. Eventually, air resistance balances the force of gravity, making the net force zero. At this point, the body stops accelerating and falls at a constant speed called terminal velocity.
Q3: Does terminal velocity exist in space?
No. In the vacuum of space, there’s no air resistance, so objects don’t reach terminal velocity — they keep accelerating under gravity.
Q4: What’s the terminal velocity of a feather?
A feather has a very low terminal velocity (around 1 m/s) because of its light weight and large surface area. That’s why it floats down slowly.
Q5: How does a parachute use terminal velocity?
A parachute increases the surface area and drag, drastically lowering terminal velocity so the skydiver lands safely at a controlled speed.