First, junior high school physics formula
1, speed formula: speed = distance ÷ time, v = s ÷ T. Time formula: time = distance ÷ speed, t = s ÷ v. Distance formula: distance = speed× time, s = v× T. Pressure formula: pressure = pressure.
2. Buoyancy formula: Buoyancy = displaced liquid volume × liquid density × gravitational acceleration, and F=ρgV row. The formula of work: work = force × distance, W=Fs. Power formula: power = working time, p = w ÷ T. Electric power formula: electric power = current × voltage, P=UI. Heat formula: heat = specific heat capacity × mass × temperature change, q = cm δ t.
Second, high school physics formula
1, momentum theorem: momentum change = impulse, Δ p = i. Law of conservation of momentum: sum of initial momentum of the system = sum of final momentum of the system, m1v1+m2v2 = m1v/kloc-0'. Law of conservation of mechanical energy: the sum of initial mechanical energy of the system = the sum of final mechanical energy of the system, e 1+E2 = e 1'+E2'.
2. Conversion formula of kinetic energy and potential energy: kinetic energy increases = potential energy decreases, δ ek =-δ EP. Parallelogram rule: composite vector = vector sum of two component vectors, f =F 1+F2. Circular motion formula: linear velocity = angular velocity × radius, v = ω R. Gravitational formula: gravitational constant × mass 1× mass 2÷ distance square, F=Gm 1m2÷r? .
3. Surface tension formula: surface tension = surface tension coefficient× liquid film area, σ = γ a. Friction formula: friction = friction coefficient× positive pressure, f = μ n. Hooke's law formula: spring force = elastic coefficient× spring elongation or compression, F=kx. * * * Point force balance formula: resultant force is zero, F 1+F2=0 or F 1-F2-F3-…-Fn=0.
The function of physical formula
1. Describe natural phenomena: Physical formulas can accurately describe natural phenomena and laws, and help us understand the motion state, energy conversion, material properties and other information of objects. For example, Newton's second law, F=ma, can describe the relationship between the acceleration of an object and the force and mass.
2. Establish a mathematical model: Physical formulas are usually mathematical models composed of mathematical symbols and equations, which can help us better understand and analyze physical problems. By using mathematical tools, we can quantitatively analyze and calculate physical phenomena.
3. Prediction and deduction: Physical formulas can not only describe observed phenomena, but also be used to predict unknown phenomena and derive new physical quantities. For example, use Einstein's mass-energy equation E=mc? We can infer the energy released by the nuclear reaction.