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!

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.

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

Calculating acceleration from graphs

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.

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

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

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

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?

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

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

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?

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.

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