Wednesday, September 12, 2001

• Let's remember all those who were affected by the tragic events yesterday (9/11)

• Displacement is a vector, distance is a scalar and is always bigger than |displacement|
• In free-fall, horizontal velocity is constant (gravity only affects vertical component)
• Use final velocity components to find final speed (resultant)
• Speed is a scalar and therefore is always positive

Chapter 3:  Motion in Two Dimensions

P.3.27 - Relative velocity
    Find components of the boat's velocity relative to the water
    Find time it takes to cross river
    Use net forward speed and the time to find the distance traveled upstream

P.3.39 - Range (p.77)
    Show how to derive the equation for the range of a projectile given its initial speed and angle.
    Show how to derive the equation for the maximum height of the projectile.
    Use proportionality to find the range with a different g than Earth.
Practice problem:  What is the maximum distance that a baseball can be thrown?

P.3.41 - Acceleration in 2 dimensions
    Find speed of roadrunner by eliminating time from 2 kinematics equations.
    Find distance by substituting in distance equation the time of fall and speed when coyote reaches cliff.

ConcepTests

Demos:
Coin drop
Shoot Barney

Minute Paper:  One thing you learned today, one question or confusion you have.

Assignments:

• RWP3 - Bank Robbery  (due Friday)
• HW3b (due Friday)  Ch.3:  P 9, 21, 27, 39, 41