物理公式
力学、热力学、电磁学和光学公式
SI Units Quick Reference
Length: m
Mass: kg
Time: s
Force: N
Energy: J
Power: W
Current: A
Voltage: V
FAQ
What are the kinematic equations?
The four kinematic equations relate displacement, velocity, acceleration, and time for uniformly accelerated motion: (1) v = v₀ + at, (2) x = v₀t + ½at², (3) v² = v₀² + 2ax, (4) x = ½(v₀ + v)t.
What is the difference between mass and weight?
Mass (kg) is the amount of matter in an object and doesn't change with location. Weight (N) is the gravitational force on an object and varies with gravitational field strength (W = mg).
When is mechanical energy conserved?
Mechanical energy (KE + PE) is conserved when only conservative forces (like gravity) do work. It is not conserved when non-conservative forces (like friction or air resistance) are present.
What units should I use in physics?
Use SI units: meters (m), kilograms (kg), seconds (s), Newtons (N), Joules (J), Watts (W), Amperes (A), Volts (V), Ohms (Ω). Always convert to SI before calculating.
