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Time Distance Speed Calculations. Distance = Speed × Time. Units of Measure:. Time:. Hours. Minutes. There are 60 minutes in an hour so convert these times in minutes to hours (in decimal notation). Minutes to hours. Hours to minutes. Write as a fraction compared
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Time Distance Speed Calculations Distance = Speed × Time Units of Measure: Time: Hours Minutes There are 60 minutes in an hour so convert these times in minutes to hours (in decimal notation). Minutes to hours Hours to minutes Write as a fraction compared with 60 minutes (in an hour) Multiply by 60 30 60 30 minutes = 0.5 hrs 2 hours 2× 60 = 120 mins 15 60 15 minutes = 0.25 hrs 0.75 hours 0.75× 60 = 45 mins
Time Distance Speed Calculations Distance = Speed × Time Units of Measure: Distance: Kilometres Miles Metres Means ÷ Speed: Kilometres per hour km/hr km/hr Miles per hour miles/hr Metres per second m/s The calculation is given by the units of measure Distance Time Speed =
Time Distance Speed Calculations Distance = Speed × Time D = S × T • Use this formula to find the distances for: • 20 miles per hour for 2 hours • 60 miles per hour for 4 hours • 40 kmph for 30 minutes • 80 miles per hour for 15 minutes • 42 km per hour for 10 minutes 20 × 2 40 miles 60 × 4 240 miles 40 × 30 60 20 km 80 × 15 60 20 miles 42 × 10 60 7 km
Time Distance Speed Calculations Distance = Speed × Time Using what we have learnt from rearranging equations If D = S × T then D = S × T and D = S × T
Time Distance Speed Calculations Speed = Distance Time • Use this formula to find : • A train travels 240 km in 4 hours • What is its average speed? • A plane flies over two cities that are 63 miles apart. • The journey takes 7 minutes. What is its average speed? • Answer in miles per minute • 3. An athlete can run 100 metres in 12 seconds. Calculate the • athlete’s speed. • Answer in metres per second and 1 d.p. • A cheetah took 6 seconds to run 150m. How fast did it run? • Answer in metres per second 240 4 = 60 km per hour 63 7 = 9 miles per minute 100 12 = 8.3 m per second 150 6 = 25 m per second
Time Distance Speed Calculations Time = Distance Speed • Use this formula to find : • A man ran 400 m at an average speed of 8 m/s • How long did he take? • A coach travels 120 miles at an average speed of 40 mph. • How long did it take? • A walker travels a distance of 3 km at a steady speed of 4km. • Find how long he takes in minutes. • A cyclist travelled 6 km at 18 kmph. • Find how long he takes in minutes. 400 8 = 50 seconds 120 40 = 3 hours 3 4 = 0.75 hrs 0.75× 60 = 45 mins . . 6 18 = 0.3 hrs = 20 mins 0.3× 60
Time Distance Speed Calculations • A delivery van sets off at 07:45 to deliver a package 20 miles • from the store. It arrives at the customer at 08:10 • Calculate the van’s average speed in miles per hour • The van’s average speed on the return journey is 25 mph. • b) How long does the return journey take? • Give your answer in minutes. • c) Calculate the van’s average speed for the whole journey. 25 60 20 0.4167 = 0.4167 hrs = 48 miles per hour 20 25 = 0.8 hrs 0.8× 60 = 48 mins 40 miles for (25 + 48) = 73 minutes 73 60 40 1.2167 = 1.2167 hrs = 32.9 miles per hour