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Speed Objectives 1.3 recall and use the relationship between average speed, distance moved and time: average speed = distance moved/time taken STARTER.

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Presentation on theme: "Speed Objectives 1.3 recall and use the relationship between average speed, distance moved and time: average speed = distance moved/time taken STARTER."— Presentation transcript:

1 Speed Objectives 1.3 recall and use the relationship between average speed, distance moved and time: average speed = distance moved/time taken STARTER TASK 1.What is the formula for calculating speed? 2.What is meant by Average Speed? 3.A car travels 70km at an average speed of 35km/hr. How long was the journey? Give units.

2 What are the units of speed when: 1.Distance is measured in metres and time in seconds 2.Distance is measured in miles and time in hours 3.Distance is measured in kilometres and time in hours 4.Distance is measured in metres and time in minutes 5.Distance is measured in millimetres and time in seconds

3 Speed speed = distance time In physics speed is usually measured in: metres per second (m/s)

4 also: distance = and: time = speedtime distance speed x time distance speed

5 6 = 12 2 What else do you know? 2 = = 6 x 2 2 = 10 5 What else do you know? 5 = = 5 x 2 5 = = = 5 x 3 What else do you know?

6 Speed = Distance Time What else can you tell me? 2 = 10 5 Based on the above equation, how do I work out distance? Based on the above equation, how do I work out time? Distance = Speed x Time Time = Distance ÷ Speed

7 Usian Bolt ran 100m in 9.58 seconds, what was his average speed? m/s (23 mph)

8 Pairs of cameras spot your number plate, start a timer, and then spot your number plate again leaving a zone 800m The speed cameras record that a car takes 350 seconds to move between them. Calculate the average speed of the car. Show your working. Give the unit. Question m/s

9 Charlie Adam takes a free kick, He is 26 metres away from the goal and it took 1.02 seconds before it crosses the goal line. How fast does the ball travel? (metres / second) (x2.24 to get Miles an Hour) = 57 mph

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12 Activity 1 Plot these results on a speed time graph, with time on the bottom axis (the x axis) and speed on the side axis (the y axis). Label the points where there is a change in motion A,B,C,D,E,F,H,I,J and K. Example: point A is at time 0 and speed 0.

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14 If you walk for 1 1 / 2 hours at an average speed of 4 miles/h. How far will you have walked? Distance = Speed × Time Distance = 4 × 1.5 = 6 miles How long does it take to drive to Leeds from Blackpool (85 Miles) if you travel at an average speed of 60 mph? Time = Distance ÷ Speed Time = 85 ÷ 60 = 1 Hour and 41 Minutes

15 1 meter per second = (2.24) mph. So, take meters per second and multiply by (2.24) to get miles per hour. Example, 55 meters per second = mph. 1m/s = mph Read more: into_miles_per_hours#ixzz1IZCtHIRhhttp://wiki.answers.com/Q/How_do_you_convert_meters_per_second_ into_miles_per_hours#ixzz1IZCtHIRh NZ8

16 To work out the speed of an object you need to know: Distance, time and speed the distance travelled; how long it took to travel that distance.

17 A boy takes 1 hour to travel from his home to the cinema, a distance of 10 km. Calculate his average speed in km/h. d sxt Cover the quantity to be calculated - s (speed) = 10 km/h Speed calculation example 10 km 1 h = d (distance in km) average speed (in km/h) t (time in h) =

18 3600 s 10,000 m = = 2.8 m/s Sometimes the units have to be changed in a speed calculation. Here is the same problem but with different units: 1x60x60 Speed calculation example – units check A boy takes 1 hour to travel from his home to the cinema, a distance of 10 km. Calculate his average speed in m/s. d (distance in m) average speed (in m/s) t (time in s) = d sxt Cover the quantity to be calculated - s (speed)

19 = 3.6 km/h x 2 h distance (km) = speed (km/h) x time (h) Question 1 A group set off from home and walk at an average speed of 3.6 km/h. How far would they travel in two hours? Give your answer in km. d sxt Speed calculation – question 1 = 7.2 km

20 10 km 5.4 km/h = Question 1 How long would it take a woman to walk 10 km if her average speed is 5.4 km/h ? d sxt time = distance speed Speed calculation – question 1 = 1.85 hours


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