Lesson 2

• Projectile motion is made of horizontal and vertical motions that are independent of each other
• Since no horizontal force acts on the projectile during its fall, its horizontal velocity is constant. Horizontal acceleration 𝒂𝒙 equals zero
• The vertical motion of the projectile is influenced by gravity causing it to accelerate vertically. Its acceleration along the vertical plane equals the acceleration due to gravity g = -9.8

  𝒎

  𝒔𝟐
• The initial horizontal velocity of the projectile


  Compares with its horizontal velocity at any point in its trajectory
• The acceleration of the projectile


  At any point of its parabolic trajectory
• Tracing the Trajectory


  1. Investigate the relationship between the angle of release and the height and range of the projectile

  2. Coat the marble or bottle cap with face powder or flour

  3. Place it on the launching pad of the retractable pen

  4. Launch the marble at 150 angle and trace the powder-marked trajectory

  5. Repeat for angles 30, 45, 60, and 75
• Projectile trajectories


  • The shape is parabolic
  • The range increases as launch angles are increased up to 450
  • The range decreases for projection angles greater than 450
  • The maximum height reached by the projectile increases as the projection angle increases
• Momentum


  The quantity of motion that an object has
• Momentum


  Mass in motion
• Momentum is directly proportional to an object's mass and directly proportional to the object's velocity
• Momentum


  • 2250 kg pickup truck with a velocity of 25

  𝑚

  𝑠 to the east

  • 23kg cannon shell going 530

  𝑚

  𝑠 to the right
• Momentum


  A vector quantity that describes both the magnitude and direction of an object's motion
• The direction of the momentum vector is the same as the direction of the velocity vector
• Calculating momentum


  p = mv
• The momentum of the 23kg cannon shell going 530 m/s to the right is 12,190 kg·m/s, right
• Impulse


  The product of the force applied on an object and the time the force acts on the object
• Impulse


  Equal to the change in momentum of the object
• The greater the net force on an object, the greater the change in velocity and thus the change in momentum
• The longer the time a force acts, the greater the change in momentum
• Momentum is the product of an object's mass and velocity
• Impulse is determined by multiplying the force applied on the object and the time the force acts on the object
• The change in momentum of an object is equal to the impulse experienced by the object
• As launch angle increases, the range increases for angles 0-45 degrees
• For projection angles greater than 45 degrees, the range decreases as the launch angle increases
• As launch angle increases, the altitude covered by the projectile also increases
• Momentum


  The product of an object's mass and velocity
• The momentum of a 10 kg bowling ball moving at 6 m/s is 60 kg·m/s
• If an object's mass doubles while its speed remains the same

  Its momentum doubles
• Determining the momentum of vehicles


  Multiply each vehicle's mass with its velocity
• Determining the impulse from a force applied on a vehicle


  Multiply the force applied on the vehicle with the time the force is applied