1. 2_4 On the Road Look at the data for the BMW 3 Series below. What is the connection between power and acceleration? 10 February 2016 ModelAcceleration 0 – 62 mph in s Power kW Mass kg 3189.11051435 3208.21251445 3256.71601535 3306.12001555 3355.62251610

2. 2_4 On the Road 10 February 2016 ModelAcceleration 0 – 62 mph in s Power kW Power x Acc n Mass kg 3189.11059561435 3208.212510251445 3256.716010721535 3306.120012201555 3355.622512601610 Any similarities?

3. 2_4 On the Road What is the resultant force at constant velocity? What does the stopping distance of a vehicle depend on? What factors increase stopping distance? 10 February 2016 The “Bloodhound” supersonic car is aiming to go faster than 1000mph! Not even a plane has been that fast at sea level!

4. Why do cars have a top speed? ModelTop speed, mph Power, kW X3 2.0 D127130 120D142130 320D143130 520D144130 520D Tourer139130 X3 120D 320D 520D Tourer What does this table tell you about these cars? What must happen to the forces at top speed for there to be no acceleration?

5. Forces on cars No resultant force means no acceleration. Top speed is reached when the _________ from the ________ equals the _________ from the air resistance. Force from engine Air resistance

6. Stopping distances What happens if the thrust force reduces? How much distance would this need to stop at 500 m/s? Car travelling at 1000mph Drag force Thrust force

7. Stopping distances What happens if the thrust force reduces? Car slows down. How much distance would this need to stop at 500 m/s? Around 2.5 miles! Car travelling at 1000mph Drag force Thrust force

8. Highway code stopping distances Thinking distance = distance covered before brakes are applied. Braking distance = distance covered while braking.

9. What can increase stopping distance? Thinking distanceBraking distance

10. Summary Thinking distance is how far a car travels before a driver hits the brakes. Braking distance is how far the car travels while braking. Stopping distance is thinking distance + braking distance.