# Equations and important concepts

 Sin (0) 0 Sin(30) 0.5 Sin(45) 0.7 Sin(60) 0.87 Sin(90) 1 Cos(0) 1 Cos(30) 0.87 Cos(45) 0.7 Cos(60) 0.5 Cos(90) 0 SOH CAH TOA Sin (θ)= O/HCos (θ)= A/HTan (θ)= O/A Force m*a Mass*accelerationKg*m/s² Joules derivation-using work formula W=F*dJ=N*mJ=(Kg*m/s²)*mJ=Kg*m²/s² Joules derivation-using Energy formula KE=1/2mv²J=Kg(m/s)²J=Kg*m²/s² PE:mgh J=Kg(m/s²)mJ=Kg*m²/s² Watts derivation-using the power formula P=W/T Power=Work/Time W=J/sW=N*m/sW=(Kg*m/s²)(m/s)W=Kg(m²/s²) Vector Magnitude + direction Scalar Magnitude ONLY Displacement vs distance Displacement is how far you are from where you started in a straight line path,while distance is the total steps you took to get there regardless of the path.Displacement is a vectorDistance is a scalar Velocity V=∆d/∆t Velocity equals the change in distance over timem/s ****Note: Velocity includes both magnitude and direction, speed is only the magnitude Acceleration a=∆V/TAcceleration equals the change in velocity over timem/s² ****Note: Since acceleration is proportional to Velocity, when velocity changes EITHER IN MAGNITUDE OR DIRECTION, acceleration changes! @Rest=no acceleration Constant velocity=no acceleration Gravity 10(m/s)/s *Every second your velocity changes by 10m/s -Sec 0= 0m/s -Sec 1= 10m/s -Sec 2= 20m/s When is g positive or negative in a problem? Consider the three variables: Acceleration (a), Velocity (V) and Displacement (d) *if all three point in the same direction, then it doesnt matter, they can all be + or - *If one of them points in a different direction, then you have to pick a point of reference and stick to it. Which equation can be use when there is NO a? d=vt distance=velocity*time Which set of equations is available when there is a? d=(Vavg)(t)d= Vi*t + (1/2)at²Vf²=Vi² + 2adVf= Vi + at or *When Vi=0 d=(Vavg)(t) d= Vi*t + (1/2)at² Vf²=Vi² + 2ad Vf= Vi + at In the graph of Displacement vs Time, what does the slope mean? Does the area under the curve have any meaning? The slope is VelocityNo, the area under the curve is useless In the graph of Velocity vs Time, what does the slope mean? Does the are under the curve have any meaning? The slope is accelerationYes, the area under the curve is displacement What's Newton's first law? , then velocity is constant *A body in motion will stay in motion if no there is no net force being applied on the body. Or a body at rest will stay at rest unless there is a net force being applied on the body What's Newton's second law? Force=mass*acceleration What's Newton's Third Law? Every force has an equal and opposite force Authorraquelvsuarez ID273569 Card SetEquations and important concepts DescriptionEquations and Important concepts Chad's videos All Physics' days Updated2014-05-07T06:14:38Z Show Answers