1. Complete the sheet on speed-time graphs… you have 15 mins
Complete the sheet on speed-time graphs… you have 15 mins! Strictly Practice makes perfect!

2. Learning Objectives By the end of this lesson you should be able to...
Interpret speed-time graphs to calculate acceleration and distance travelled by objects.
Use speed-time graphs and formulas for acceleration to show how crumple zone technologies save lives.
Determine how the force acting on an object can be calculated from the its acceleration and mass.

3. What’s the acceleration?
What is the acceleration of the object between points A and B?
time (s)
speed (m/s) 2 1 3 4 5 6 7 8 10 15 20 25 30 35 A B
The object’s speed has increased by 20 m/s (25 - 5)
It took 4 s to change speed (6 - 2)
Acceleration = speed/time
= 20/4
= 5 m/s2

4. Calculating acceleration from graphs

5. Area under a speed–time graph
Teacher notes
This six-part animated sequence provides a step-by-step guide to how the distance travelled by an object can be calculated from the area underneath its speed–time graph.

6. Acceleration Formulae
Learning Objectives
By the end of this lesson you should…
Interpret speed-time graphs to calculate acceleration and distance travelled by objects.
Use speed-time graphs and formulas for acceleration to show how crumple zone technologies save lives.
Determine how the force acting on an object can be calculated from the its acceleration and mass.
Acceleration Formulae
Acceleration can be found in several ways;
a = v – u t
a = F m

7. a = v – u t a = F m Acceleration Formulae Worked example:
Learning Objectives
By the end of this lesson you should…
Interpret speed-time graphs to calculate acceleration and distance travelled by objects.
Use speed-time graphs and formulas for acceleration to show how crumple zone technologies save lives.
Determine how the force acting on an object can be calculated from the its acceleration and mass.
Acceleration Formulae
Worked example:
A car crash results in a car decelerating from 43m/s to 0 in 0.02s. What is the (de)acceleration?
a = v – u t
a = F m

8. a = v – u t a = F m Acceleration Formulae Worked example:
Learning Objectives
By the end of this lesson you should…
Interpret speed-time graphs to calculate acceleration and distance travelled by objects.
Use speed-time graphs and formulas for acceleration to show how crumple zone technologies save lives.
Determine how the force acting on an object can be calculated from the its acceleration and mass.
Acceleration Formulae
Worked example:
If the loaded car weighs 1150kg then what is the force acting during the deceleration?
a = v – u t
a = F m

9. Learning Objectives
By the end of this lesson you should…
Interpret speed-time graphs to calculate acceleration and distance travelled by objects.
Use speed-time graphs and formulas for acceleration to show how crumple zone technologies save lives.
Determine how the force acting on an object can be calculated from the its acceleration and mass.
So… how might we be able to design a car to reduce the force experienced in accidents?

10. So… how might we be able to design a car to prevent
Learning Objectives
By the end of this lesson you should…
Interpret speed-time graphs to calculate acceleration and distance travelled by objects.
Use speed-time graphs and formulas for acceleration to show how crumple zone technologies save lives.
Determine how the force acting on an object can be calculated from the its acceleration and mass.
So… how might we be able to design a car to prevent
accidents?
Crash test with and without airbag
Airbag deployment in slow-motion
Volvo Crumple Zone
With Vs Without Crumple Zone

11. Match the following statements to your safety features:
Learning Objectives
By the end of this lesson you should…
Interpret speed-time graphs to calculate acceleration and distance travelled by objects.
Use speed-time graphs and formulas for acceleration to show how crumple zone technologies save lives.
Determine how the force acting on an object can be calculated from the its acceleration and mass.
Match the following statements to your safety features:
changes shape which absorbs kinetic energy
increases the time taken for the car to stop
cushions the impact
absorbs kinetic energy by stretching a little bit
increases the time taken by the passenger to stop
a strong metal cage that protects the occupants
prevents driver distraction

12. Which car has the best crumple zone?
Learning Objectives
By the end of this lesson you should…
Interpret speed-time graphs to calculate acceleration and distance travelled by objects.
Use speed-time graphs and formulas for acceleration to show how crumple zone technologies save lives.
Determine how the force acting on an object can be calculated from the its acceleration and mass.
Which car has the best crumple zone?

13. Which car has the best crumple zone?
Learning Objectives
By the end of this lesson you should…
Interpret speed-time graphs to calculate acceleration and distance travelled by objects.
Use speed-time graphs and formulas for acceleration to show how crumple zone technologies save lives.
Determine how the force acting on an object can be calculated from the its acceleration and mass.
Which car has the best crumple zone?
Calculate the force acting in both cases if the loaded car weighs 1138kg.

14. Now work your way through the calculations.
Learning Objectives
By the end of this lesson you should…
Interpret speed-time graphs to calculate acceleration and distance travelled by objects.
Use speed-time graphs and formulas for acceleration to show how crumple zone technologies save lives.
Determine how the force acting on an object can be calculated from the its acceleration and mass.
Now work your way through the calculations.
Finished?
Try the extension Q’s
Finished… some more…
- Text book P