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urp:physgen [2021-11-05] nerf_herder |
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- | ==== General Physics ==== | + | ===== General Physics ===== |
- | * [[#Newton's 3 laws]] | + | |
- | * [[#Distance, time, velocity, acceleration]] | + | |
- | * [[#Collisions]] | + | |
- | * [[#Inclined plane]] | + | |
- | * [[#Spring and lever]] | + | |
- | * [[#Projectile fired at an angle]] | + | |
- | * [[#Buoyant force]] | + | |
- | * [[#Gravity]] | + | |
- | * [[#Kinematics]] | + | |
- | * [[#Miscellaneous]] | + | |
====Newton's 3 laws==== | ====Newton's 3 laws==== | ||
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When parallel force > friction, it is unbalanced and objects will move down the plane | When parallel force > friction, it is unbalanced and objects will move down the plane | ||
Applied force - friction = net force | Applied force - friction = net force | ||
+ | |||
+ | ====Friction==== | ||
+ | Coefficient of friction | ||
+ | * μ = f/N (force applied divided by Normal force) | ||
+ | * fNet = fApp - Ffriction | ||
static friction - | static friction - | ||
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N = normal force) must be overcome before the mass moves | N = normal force) must be overcome before the mass moves | ||
μS = fs/N = m*g*sin(θ) / m*g*cos(θ) = sin(θ)/cos(θ) = tan(θ) | μS = fs/N = m*g*sin(θ) / m*g*cos(θ) = sin(θ)/cos(θ) = tan(θ) | ||
- | kinetic friction - normal moving friction | + | kinetic friction - moving friction |
only one type of friction applies at a time | only one type of friction applies at a time | ||
- | |||
- | ====Spring and Lever==== | ||
- | **Hooke's law** for springs: F=-kx, k=spring constant, x = displacement | ||
- | |||
- | **Fulcrum**: t = r * f (torque = radius * force) | ||
- | just add the torques for multiple objects on one side of a fulcrum | ||
- | |||
- | ====SHM - Simple Harmonic Motion==== | ||
- | ma = -kx | ||
- | |||
- | angular frequency ω = √(k/m) | ||
- | |||
- | period of oscillation T = 2π √(m/k) (horizontal or vertical springs) | ||
- | |||
- | In a vertical spring, the weight Mg of the body produces an initial elongation to equilibrium, such that Mg − kyₒ = 0. | ||
- | |||
- | If y is the displacement from this equilibrium position the total restoring force will be Mg − k(yₒ + y) = −ky | ||
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vf²= vo² + 2ad | vf²= vo² + 2ad | ||
vf = v0 + at | vf = v0 + at | ||
+ | |||
+ | |||
+ | ====Optics==== | ||
+ | Refraction on going into a different medium | ||
+ | |||
+ | **Snell's law** | ||
+ | sin(θ₁) / sin(θ₂) = v₁/v₂ = n₂/n₁ (note that the n values are reversed) | ||
+ | v = velocity of light in that medium, n = index of refraction | ||
+ | v = c/n (c = speed of light in a vacuum) | ||
+ | it bends towards the normal direction when entering denser material | ||
+ | (and slows down). bend is because photons are waves. | ||
+ | |||
+ | Critical angle : smallest angle that results in total reflection, no refraction | ||
+ | θc = arcsin(n₂/n₁) | ||
+ | |||
====Miscellaneous==== | ====Miscellaneous==== |