Projectile Motion · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Two lives of a flying ball

Mathematics · Mechanics · ages 17-18
Name ______________________   Date ____________

  1. A ball launches at 25 m/s with cos(theta) = 0.8. What is the horizontal component in m/s?

    Answer: ______________

  2. A ball launches at 25 m/s with cos(theta) = 0.8 and sin(theta) = 0.6. What are its components?

    • 15 m/s horizontal and 20 m/s vertical
    • 25 m/s in both directions
    • 20 m/s horizontal and 15 m/s vertical
    • 20 m/s vertical and 15 m/s horizontal

  3. A ball launches at 25 m/s with cos(theta) = 0.8 and sin(theta) = 0.6. What are its components?

    • 20 m/s horizontal and 15 m/s vertical
    • 15 m/s horizontal and 20 m/s vertical
    • 25 m/s in both directions

  4. The standard projectile model ignores air resistance.

    Circle one:   True   False

  5. A projectile flies with horizontal speed 20 m/s for 3 s. What is its range in metres?

    Answer: ______________

  6. With no air resistance, horizontal velocity stays constant through the flight.

    Circle one:   True   False

  7. A projectile launches with vertical speed 15 m/s and lands at launch height. Take g = 10. What is the time of flight?

    • 1.5 s
    • 3 s
    • 6 s
    • 15 s

  8. With no air resistance, horizontal velocity stays constant through the flight. True or false?

    Circle one:   True   False

  9. A projectile flies with horizontal speed 20 m/s for 3 s. What is its range in metres?

    Answer: ______________

  10. At the very top of its flight, the vertical velocity of a projectile is what?

    • 15 m/s
    • 20 m/s
    • 25 m/s
    • zero
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Answer key

For grown-ups. Fold this page away before handing over the rest.

Two lives of a flying ball W1-mt_O1C-QxCSJN-s1

  1. 20 · 20. Note 25 times 0.8 = 20.
  2. 20 m/s horizontal and 15 m/s vertical · 20 m/s horizontal and 15 m/s vertical. Multiply 25 by 0.8 and by 0.6.
  3. 20 m/s horizontal and 15 m/s vertical · Multiply 25 by 0.8 and by 0.6.
  4. True · Leaving drag out keeps horizontal velocity constant and the maths clean.
  5. 60 · 60. Range = horizontal speed times time = 20 times 3.
  6. True · No horizontal force means no horizontal acceleration.
  7. 3 s · 3 s. Up takes 15/10 = 1.5 s and down takes as long again.
  8. True · True. No horizontal force means no horizontal acceleration.
  9. 60 · Range = horizontal speed times time = 20 times 3.
  10. zero · Zero. The projectile instantaneously stops rising before falling back.
Worksheet · LightMySky