Memory Anchor:

• Answer question on relative motion eg: trains and cars passing one another

Super Challenge:

Stretch:

Challenge:

Key Questions:

1. What is the difference in speed between a car travelling a 30 m/s and a lorry travelling at 20 m/s? How did you work this out? What does this difference in speed show?
   • What is the difference in speed between a car travelling a 30 m/s and a lorry travelling at 20 m/s? => 10 m/s How did you work this out? => 30 take away 20 This is the relative motion between the car and the lorry.
2. What is meant by 'relative motion'?
   • The relative motion is the 'motion' (movement) of one object measured 'relative' (from) another.
3. How much further does the car get away from the lorry in one second? What if the car starts behind the lorry?
   • How much further does the car get away from the lorry in one second? => 10 m/s What if the car starts behind the lorry? => The car would get closer, maybe collided at 10 m/s.
4. At what speed would they collide at if they were travelling towards each other? How did you work this out?
   • At what speed would they collide at if they were travelling towards each other? => 50 m/s How did you work this out? => 30 plus 20
5. What is velocity? What is negative velocity?
   • Velocity is speed in a direction. A negative velocity is in the opposite direction to a positive one.
6. If the lorry is travelling at 20 m/s and a car at -30 m/s what speed do they collide at? How did you work this out?
   • If the lorry is travelling at 20 m/s and a car at -30 m/s what speed do they collide at? => 50 m/s How did you work this out? => 20 take away minus 30