1. What is E=mc²?

E=mc² is Einstein's famous mass-energy equivalence formula from his theory of special relativity. It states that energy (E) and mass (m) are interchangeable, with c² (speed of light squared) as the conversion factor.

2. How Does the Calculator Work?

The calculator uses Einstein's equation:

Where:

• \( E \) — Energy (Joules)
• \( m \) — Mass (kilograms)
• \( c \) — Speed of light in vacuum (299,792,458 m/s)

Explanation: The equation shows that even a small amount of mass can be converted into a tremendous amount of energy due to the large value of c².

3. Importance of Mass-Energy Equivalence

Details: This principle underlies nuclear reactions, explains the energy source of stars, and revolutionized our understanding of physics. It shows that mass and energy are different forms of the same thing.

4. Using the Calculator

Tips: Enter mass in kilograms and speed of light in m/s (default is 299,792,458 m/s). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: Why is the speed of light squared in the equation?
A: The c² factor comes from the mathematical derivation of the equation in special relativity and represents the enormous energy contained within mass.

Q2: How much energy is in 1 kg of mass?
A: Using c = 299,792,458 m/s, 1 kg is equivalent to about 89,875,517,873,681,764 J (≈90 petajoules).

Q3: Can we convert all mass to energy?
A: In practice, only a small fraction of mass can be converted to energy (about 0.1% in nuclear fission, up to 0.7% in fusion).

Q4: Does this equation apply to all energy?
A: This represents rest energy. Moving objects have additional kinetic energy described by the full relativistic energy equation.

Q5: Why don't we notice E=mc² in daily life?
A: The effects are negligible at everyday speeds and energy scales, becoming significant only at nuclear or cosmic scales.