Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Things You Should Know About Physics Regents First Quarter Fundamental units Mechanics Mass (m): = inertia, amount of matter, constant from place to place, units: kg Weight (Fg): = force of gravity, changes from place to place, units: N Formula: Quantity Units Symbol Length meter m Mass kilogram kg Time Electric current Temperature second s ampere A kelvin K Fg = mg Derived units Equilibrium: no net force, no acceleration, constant Quantity symbol velocity or at rest, forces form a closed figure. Velocity m/s acceleration m/s2 N/kg force N Kg m/s kg m/s Ns Work, Heat Energy J Nm Voltage V J/C eV 1.6x10-19J N/C V/m Frequency Hz 1/sec Period sec Concurrent vectors: are added tip to tail. also Momentum Component vectors: any vector has both X and Y components. Add components to get resultant. V2 = Vx2 + Vy2 Angle : = tan-1[Y/x] Resultant force = Fnet : head-to-head and tail-to-tail with components Equilibrant: equal and opposite to resultant & Impulse Energy for subatomic Electric Field Two names for little “g”: 1) acceleration due to gravity, units: m/s2, formula: g = GM/r2 2) gravitational field strength, units: N/kg, formula: g = Fg/m Scalars (magnitude only) Distance Speed Mass speed Anything else! Vectors (magnitude and direction) – only 9! Displacement Velocity Acceleration Force (weight, normal force, etc.) Momentum Impulse Fields (gravitational, electric, magnetic) Kg m2/s2 Things You Should Know About Physics Vectors d Resultant Concurrent t Equilibrant Maximum 2 Θ = 00 Minimum 2 Θ = 1800 5 Slope = velocity 7 5 3 Triangle rule sum of any 2 sides ≥ third side for forces to be in equilibrium Constant Velocity Graphs of Motion v Two Types of Motion Constant Acceleration Forces are balanced Fnet = 0, a = 0 In equilibrium Newton’s first law Forces are unbalanced Fnet ≠ 0, a ≠ 0 not in equilibrium Newton’s second law Distance v. Speed v. time time Distance v. Speed v. time time Acceleration v. time Acceleration v. time Friction Static friction (at rest) = applied force until motion starts Kinetic friction (in motion) is constant Maximum static friction is greater than kinetic friction Newton’s Third Law: Whenever A exerts force on B, B exerts equal/opposite force on A. (Action/reaction pairs: bat and ball, Earth and Moon, hammer and nail) Forces are the same but the effects of the forces are not: mA = Ma t Slope = acceleration Area = displacement Things You Should Know About Physics