Projectile motion

Starter Watch the video... Why can the golf ball be described as a projectile? What is the shape that the balls path creates?

Learning objectives Explain what a projectile is. Explain the behaviour of projectiles as they move. Use the equations of motion for an object projected horizontally above the Earth’s surface.

Success criteria Produce a labelled diagram showing the key features of a projectiles motion. (Grade C) Calculate different values for a projectiles motion using equations of motion. (Grade A)

Projectiles – key facts A projectile is an object which moves through the Earth’s gravitational field. Projectiles which are thrown horizontally or at an angle to the ground follow a curved parabolic path, called the trajectory. The sideways motion of a projectile has no effect on its downwards motion When performing calculations treat the vertical and horizontal motions as two separate ones

Demo / experiment Ruler and ball experiment Video if required

Look at page 183 of the text book old course Sketch figure 3 and annotate it to describe: How far the ball travels horizontally in a given time. How far the balls fall each second in relation to each other. How the distance the balls fall each second changes (why is this?)

Newton’s projectile Page 183 - old course

Calculations on projectiles

Projectile Motion Aha! If I let go of the branch when he fires his gun I’ll be safe because the bullet will go above me…

Question – how long did this take and how fast was the bullet? Projectile Motion 1.5m Question – how long did this take and how fast was the bullet? 50m Use s = ut + ½at2 vertically to find the time Then use speed = distance / time horizontally to get the speed

Monkey_and_hunter_classroom.mp4 Look at the example of the thrown dart on page 183. Monkey_and_hunter_classroom.mp4

Foundation: 1. Answer Q3 and 4 page 183 2 Foundation: 1. Answer Q3 and 4 page 183 2. Sketch and explain Newton’s projectile Higher: Try the questions on the projectiles worksheet. v = u + at v2 = u2 + 2as s =(u + v)t s = ut + ½at2 2

Answers Foundation: 10 m/s2 vertically downwards a) 15 m/ b) i 20 m ii 80 m; time doubles but distance fallen is four times bigger

Answers Higher: a. t = 10 b. distance = 1500m 2. using speed = distance/time t = 0.5 Using s = ut + ½at2 s = 1.25m 3. a. 0.4s b. 5m/s 4. a. 3s b. 30m/s c. 30m/s d. 90m 5. a. 3s b. 30m/s c. 15m/s d. 45m 6. 0.35s 0.84m 7. 2.1s 16.7m/s

Learning objectives Explain what a projectile is. Explain the behaviour of projectiles as they move. Use the equations of motion for an object projected horizontally above the Earth’s surface.

Success criteria Produce a labelled diagram showing the key features of a projectiles motion. (Grade C) Calculate different values for a projectiles motion using equations of motion. (Grade A)

Plenary Write definitions for the following key words: Projectile Trajectory Parabolic