Projectile Motion (DP IB Physics: SL)

• The trajectory of an object undergoing projectile motion consists of a vertical component and a horizontal component
  • These need to be evaluated separately

• Some key terms to know, and how to calculate them, are:
  • Time of flight: how long the projectile is in the air
  • Maximum height attained: the height at which the projectile is momentarily at rest
  • Range: the horizontal distance travelled by the projectile

How to find the time of flight, maximum height and range

Problems involving projectile motion

• There are two main considerations for solving problems involving two-dimensional motion of a projectile
  • Constant velocity in the horizontal direction
  • Constant acceleration in a perpendicular direction

• The only force acting on the projectile, after it has been released, is the gravitational pull of the Earth on the object, or weight
• There are three possible scenarios for projectile motion:
  • Vertical projection
  • Horizontal projection
  • Projection at an angle

Step 1: Consider the situation

• In this question, vertical motion only needs to be considered to find the vertical height

Step 2: List the known quantities

• u = 12sin(50) ms⁻¹
• v = 0 ms⁻¹
• a = −9.81 ms⁻²
• s = ?

Step 3: State the correct kinematic equation

Step 4: Rearrange the equation to make height, s the subject

Step 5: Substitute in the known quantities and calculate  maximum height, s