1. Learning Objectives : 1.To recognise projectile-like problems 2.To check understanding via motion graphs 3.To set the scene for harder problems Book References : Pages 128-129 & 122-123

2. Projectile-like motion: During the last lesson we looked at the motion of falling objects given a horizontal projection

3. This can be used to consider the motion of any object which experiences: A constant velocity in one direction and a constant acceleration in another.... For example: 1.A ball rolling across an inclined plane 2.Electron beam between charged plates

4. An example.... A ball is projected horizontally at 0.52 ms -1 across the top of an inclined board which is 60cm wide (horizontally) and 120cm high (vertically in the direction of the incline). The ball reaches the bottom of the board in 0.9s. Calculate the following: a)The distance travelled across the board [0.468m] b)Its acceleration on the board [2.96ms -2 ] c)Its speed at the bottom of the board [2.8ms -1 ]

5. Motion graphs for projectile motion : For example consider an object thrown upwards: Displacement Time Maximum height Distance Time Maximum height

6. Motion graphs for projectile motion : For example consider an object thrown upwards: Displacement Time Maximum height Distance Time Maximum height

7. Velocity Time Maximum height

8. Velocity Time Maximum height +u -u t=u/g

9. More challenging problems (a taster) So far the most difficult scenario we’ve considered is purely horizontal projection under the influence of gravity.... What about firing something from a gun with an initial vertical velocity or using a golf club other than a putter? Not required for our specification. But those taking Maths are likely to come across it in Mechanics 2

10. Vertical component Horizontal component Maximum height θ U This is the general case How can we find the horizontal and vertical components of the initial launch speed U? Can you derive the previous special case/simplified equations for vertical only and horizontal only projection?

11. Summary 1.Only simple vertical only and/or horizontal only projection is considered by our AS specification 2.Remember motion graphs can be asked and aid understanding 3.We’ve touched on how to deal with the general case of being launched with a projection at an angle 4.Which, skill wise leads us nicely to the next topic