A swim across a lake A cycle around the lake The distances covered and times taken for each section are Calculate Dons average speed in kilometres per hour for the swim section Calculate Dons average speed for the entire race ID: 815051
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Slide1
Questions
Slide21.
Don competes in a biathlon race. The race has two sections:
A swim across a lake
A cycle around the lakeThe distances covered and times taken for each section are:Calculate Don’s average speed in kilometres per hour for the swim section.Calculate Don’s average speed for the entire race.
Section
Distance
Time
Swim
600 m
15 minutes
Cycle
20 km
45 minutes
Slide32 a.
When she walks to school from home, Jenny walks 260 m from her house to the main road, then half a kilometre along the main
road and
finally 120 m from the main road to the school gate.State each part of the journey as a distance in kilometres.Calculate the total distance Jenny has walked in metres and in kilometres.
Slide42 b.
Jenny hurries from her house because she is going to meet her friend
Heta
. Jenny takes 3 minutes (0.05 hours) to reach the main street. Jenny and Heta dawdle along the main road, taking 12 minutes (0.2 hours) to reach the turn-off to school. When they get there, they realise they are late, so they run to the school gate at a constant speed of 8 km h-1. Calculate Jenny’s average speed (in kilometres per hour) during the first part of her journey.Calculate Jenny’s average speed (in kilometres per hour) from home to the turn-off from the main road.Calculate the time (in seconds) it takes Jenny and Heta to run to the school gate.
Jenny’s brother, Jim, cycles the same route to school in 10 minutes. In terms of distance and time, explain how you know that Jim cycles faster than Jenny walks.
Slide53.
Section of journey
Distance
Time (h)
Speed
Wellington to Taupo
380 km
5 hours
Lunch
1 hour
Taupo to Waitomo
220 km
Coffee
½ hour
Waitomo to Auckland
2 ½ hours
80 km h
-1
Whole journey
12 hours
Slide63.b
Calculate the average speed from Wellington to
Taupo
.Calculate how long it would take to travel from Taupo to Waitomo if they average the same speed as in the first leg of their journey from Wellington to Taupo.Calculate their actual average speed from Taupo to Waitomo.
Slide73.C
Calculate the distance they travelled from
Waitomo
to Auckland.Calculate the average speed for the whole journey.Explain why the average speed for the whole journey is less than the speeds they were averaging in each section of the journey.