Physics Calculators
From Newton's laws to free fall and projectile motion — our free physics calculators solve the equations so you can focus on understanding the concepts.
Browse by Type
Motion & Forces
Velocity, acceleration, force, and Newton's laws
Energy & Matter
Kinetic energy, density, and gravitational force
Physics Glossary — Key Terms Explained
- Velocity (v)
- The rate of change of position with respect to time. A vector quantity — it has both magnitude (speed) and direction. Unit: m/s.
- Acceleration (a)
- The rate of change of velocity with respect to time. Unit: m/s². Gravity accelerates objects at 9.81 m/s² near Earth's surface.
- Force (F)
- A push or pull on an object. Defined by Newton's Second Law: F = ma. Unit: Newton (N) = kg·m/s².
- Kinetic Energy (KE)
- The energy an object possesses due to its motion. KE = ½mv². Doubling speed quadruples kinetic energy.
- Density (ρ)
- Mass per unit volume: ρ = m/V. Unit: kg/m³. Water has a density of 1,000 kg/m³ at 4°C.
Frequently Asked Questions
How do I calculate velocity?
Velocity = Distance ÷ Time (v = d/t). If an object travels 100 metres in 10 seconds, its velocity is 10 m/s. If you know initial velocity and acceleration, use v = u + at instead.
What is the formula for kinetic energy?
Kinetic energy KE = ½ × mass (kg) × velocity² (m/s). A 1,000kg car travelling at 30 m/s has KE = ½ × 1,000 × 900 = 450,000 Joules (450 kJ).
How long does it take an object to fall?
In free fall (no air resistance), time = √(2d/g) where g = 9.81 m/s². An object dropped from 10 metres takes √(20/9.81) ≈ 1.43 seconds to reach the ground.
What is Newton's Second Law?
Newton's Second Law states Force = Mass × Acceleration (F = ma). A 2kg object accelerating at 5 m/s² requires a net force of 10 Newtons. It describes how the velocity of an object changes when subjected to a force.