Exam 3

Exam 3

1. CH 10: fluids

   • pressure
     • p=f/a
       • scalar units: pascals, Pa
   • density
     • density=m/v
     • vacuum= 0 density
   • fluids and gravity
     • pressure at height= P atmosphere +(density*gravity*height)
       • Pascal's principle: pressure at one location changes, the change is transmitted throughout the liquid in a closed container
         • hydraulic lift
           • w1=w2 W1=F1y1 W2=F2y2
         • (F1/A1)=(F2/A2)
     • U-tubes and barometers
     • buoyant force
   • Fluids in motion
     • flow rt=Q=area*velocity
     • bernoulli's equation
       • pressure1+ (1/2 density*velocity1^2) +density*gravity*height= P2 + 1/2density*v2^2 + density*g*h

2. Chapter 11: Harmonic Motion and Elasticity

   • Part 1
     • Harmonic Motion
       • frequency = 1/T
         • Frequency is the number of oscillations that occur in one period of time that is usually measured in Hertz
       • Oscillatory Motion
         • y= Asin(2pift)
         • Amplitude of the Motion
           • y= + or - A
         • Period
           • T= (2pi)/omega
           • T= 1/f
         • Velocity is equal to the distance around the circle (2piA) divided by the period = T
       • General Equations
         • x= Acos(2pift)
         • v= 2pifA cos (2pift)
       • Systems that oscillate in a sinusoidal manner are called simple harmonic oscillators
       • Omega is angular velocity
   • Part 2
     • Stress, Strain, and Hooke's Law
       • Stress = Strain
         • Stress = Force / Area
         • Strain = (Modulus * (Change in Length / Length of Object))
           • Three Moduli: (elastic constants)
             • Young's Modulus (Y) - used for characterizing "stiffness" of a material
             • Shear Modulus (S) - used for characterizing a materials reaction to a shear force (one that has one end fixed and warps the other side).
             • Bulk Modulus (B) - used when a change of volume is at play
       • Hooke's Law
         • The force exerted by a spring is directly proportional to the amount that the spring is stretched or compressed
         • F = (-kx)

3. Ch 8 Rotational Motion

   • describing rotational motion
     • rotational quantities
       • Radians
         • 360 degrees = 2pi rad
       • angular position = theta
         • theta = s / r where s is arc length and r is radius
       • angular velocity = lowercase omega (fancy w)
         • w = theta / time
       • angular acceleration = alpha
         • alpha = w / time
   • torque and Newton's Laws for rotational motion
     • torque = force * radius
     • total torque or uppercase sigma torque = I * alpha
     • moment of inertia = I = dependent upon object and shape
   • rotational dynamics and equilibrium
     • rotational equilibrium
       • total torque = 0
     • rotational dynamcis
       • delta theta = (angular v)(delta time) + 1/2 (alpha)(delta time ^2)
       • final angular v = (initial angular v)+ (alpha)(delta time)
       • final angular v^2 = (initial angular v^2) + 2(alpha)(delta theta)
   • combined rotational and translational motion
     • arises in many cases
       • a rolling wheel or the motion of a baseball
     • rolling motion
       • angular v * R = v = 2(pi)R / T
       • a = alpha * R
     • baseball scenario
       • more complex than rolling motion
         • involves linear and rotational quantities, dynamics, and center of mass