In this chapter we will learn about the kinematics (displacement, velocity, acceleration) of a particle in two or three dimensions.

1
Chapter 4, part 2
Reading assignment Chapter 5.1-5.4 Homework 7
(due Monday, Sept. 12, 2005) Chapter 5 Q15, 1,
11, 18, 21, 29

• In this chapter we will learn about the
  kinematics (displacement, velocity, acceleration)
  of a particle in two or three dimensions.
• Projectile motion
• Relative motion

2
Projectile motion

• Two assumptions
• Free-fall acceleration g is _____________.
• Air resistance is ________________.

• The path of a projectile is a ________________
  (derivation see book).
• Projectile leaves origin with an initial
  velocity of vi.
• Projectile is launched at an angle qi
• Velocity vector changes in _____________ and
  _______________.
• Acceleration in y-direction (vertical) is
  _____________.
• Acceleration in x-direction (horizontal) is
  ___________.

3
Projectile motion
of motion in
x-direction and motion in y-direction
Acceleration in x-direction is 0.
Acceleration in y-direction is g. (Constant
______________) (Constant __________________)
The horizontal motion and vertical motion are
_______________ of each other that is, neither
motion affects the other.
4
Simultaneous fall demo

• Which ball will hit the ground first?
• Straight drop
• Straight out
• Both released at the same time

5
A battleship simultaneously fires two shells at
enemy ships. If the shells follow the parabolic
trajectories shown, which ship gets hit first? 1)
A. 2) B. 3) Both hit at the same time. 4)
Need more information.
6
Hitting the bulls eye. Hows that? Demo.
7
Black board example 4.2
A rifle is aimed horizontally at a target 30 m
away. The bullet hits the target 1.9 cm below the
aiming point.

1. What is the bullets time of flight
2. What is the bullets speed as it emerges from the
   rifle?

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y
Black board example 4.3
x
q
A ball is tossed from an upper-story window of a
building. The ball is given an initial velocity
of 8.00 m/s at an angle of 20 below the
horizontal. It strikes the ground 3.00 s later.

1. How far horizontally from the base of the
   building does the ball strike the ground?
2. Find the height from which the ball was thrown.
3. How long does it take the ball to reach a point
   10 m below the level of launching?

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Just to re-iterate