Velocity Calculator
What is Velocity?
In everyday language, we use the words "Speed" and "Velocity" interchangeably. But in physics, they are two completely different concepts.
- Speed: This is a "Scalar" quantity. It only measures magnitude (how fast you are going). Example: "The car is moving at 60 mph."
- Velocity: This is a "Vector" quantity. It measures both magnitude and direction. Example: "The car is moving at 60 mph North."
Why does this matter? Because if you drive in a perfect circle at 60 mph and return to your starting point, your average Speed was 60 mph, but your average Velocity was zero (because your total displacement was zero!).
The Magic Formula Triangle (v = d/t)
This calculator is built on the foundational equation of kinematics. You can rearrange the variables depending on what you are trying to find. This is often taught as a triangle in schools.
1. Solving for Velocity
Formula: v = d / t
Example: Usain Bolt runs 100 meters in 9.58 seconds.
100 ÷ 9.58 = 10.44 meters per second (approx 23 mph).
2. Solving for Distance
Formula: d = v × t
Example: A car drives at 60 mph for 2 hours.
60 × 2 = 120 miles.
3. Solving for Time
Formula: t = d / v
Example: You need to travel 300 km and your train moves at 100 km/h.
300 ÷ 100 = 3 hours.
Speed Comparison: Nature vs. Machines
To understand just how fast things move, here is a comparison of velocity across the natural and mechanical world.
| Object | Velocity (m/s) | Velocity (mph) |
|---|---|---|
| Garden Snail | 0.013 m/s | 0.03 mph |
| Human (Walk) | 1.4 m/s | 3.1 mph |
| Usain Bolt (Max) | 12.4 m/s | 27.8 mph |
| Cheetah | 33 m/s | 75 mph |
| Sound (Mach 1) | 343 m/s | 767 mph |
| Earth Orbit | 29,780 m/s | 66,600 mph |
The Universal Speed Limit
Is there a limit to velocity? Yes. According to Einstein's Theory of Special Relativity, the fastest possible velocity in the universe is the Speed of Light (c).
c = 299,792,458 meters per second.
As any object with mass approaches this speed, its mass becomes infinite, requiring infinite energy to accelerate further. This is why, currently, faster-than-light travel remains science fiction.
Terminal Velocity
On Earth, falling objects don't accelerate forever. They hit Terminal Velocity.
When a skydiver jumps from a plane, gravity pulls them down (accelerating at 9.8 m/s²). However, air resistance pushes back up. Eventually, these forces balance out, and the skydiver stops accelerating.
For a human in a belly-to-earth position, terminal velocity is roughly 120 mph (53 m/s). Use our Free Fall Calculator to explore this physics concept further.