|
|
We use distance Speed and Time
every day without realising it. Every time you plan a journey,
what time you should leave home or even what time you should arrive
is a form of calculation using distance speed and time.
The
Objectives:
1. Convert hours
and minutes into decimal time.
2. Calculate the distance of a journey when given the speed and
time taken.
3. Calculate the time taken on a journey given the distance and
speed travelled.
4. Calculate the speed travelled when given the distance and time
taken.
5. Explain the relationship between distance speed and time
6. Check your answers by clicking
the icon at the bottom of this page.
|
|
Decimal Time: 0Before
we go onto distance speed and time it is very important that
you can understand decimal time. do not move onto the remainder
of this page until you understand decimal time. (Division):
A journey takes
2 hrs and 15 minutes
Before we can
use the time above, we need to turn the minutes (15) into decimal
time
* What part of
an hour is 15 minutes ? 15 mins is 1/4 of an hour
* Convert this fraction of an hour into a decimal
1/4 = 0.25 000so,
15 minutes is now 000.25
Now our orignal
time (2hrs & 15 mins) can be converted into 2.25 hrs.
Do not
get 0.25 hrs and 0025 hrs mixed up, they are different. write
down what each time means, fill in the answer to the two questions
below.
00001.
00000000000000000000.25 hrs = ____________
(?)
00000000000000000000000000025 hrs
= ____________ (?)
|
|
Now have a go to convert the
hours and minutes into decimal time:
00002.00Express
2 hrs and 30 minutes in decimal time:
00000000000030
minutes is ___________ hr ( write this as a fraction)
00000000______
= _______ 000now
convert this fraction into a decimal
0000000030
minutes = ___________ hrs (?)
00000000Now
add on the 2 hours = ______________ hrs.(?)
|
|
0003.
ooExpress
1 hour and 45 minutes in decimal time?
|
|
The examples I have put above
are easy to do, because, as we would often say "a quarter
of an hour" instead of 15 minutes, that is easy to work
out, but what about converting 12 minutes into decimal time.
We must remember that there are 60 minutes to an hour and to
convert 12 of those minutes to decimal is:
00000000000012
0000000000--------0000000000Cancel
down = 12 0000/1000000==
1/5
00000000000060 00000000000000000000000----
0000000000000000000000000000000000000060
0000/5
What
we have to do now is to convert this fraction (1/5)
into a decimal
1/5 = 0.2
|
|
Now you can have ago at
the next one:
0004.
000Express 6 minutes into decimal
time?
|
|
If you have not
sorted the answers out yet then you need help, you should of,
by now sorted out these problems with a division sum.
However, if you have sorted hours and minutes into decimal time,
great, we now need to convert them back again, ie, decimal time
to hours and minutes, I did not say it was easy:
|
Right here we go, after doing
a sum, you get the answer of 1.4 hrs, the only thing is when
we talk to people, we do not say "well it will take you
1.4 hrs to get from here to there, so we need to convert this
time (decimal) to hours and minutes. Now then, when we convrted
the previous sums, we used division, now we are going to multiply
First, we will deal with the
.4, leave the whole number for the moment.
0.4 will represent .4 of an
hour (60 minutes) so
0.4 hrs = 0.4 x 60 = 24 minutes.
Remember we still need to put
the 1 hr on (whole number)
1.4 hrs = 1 hr 14 minutes.
|
|
Now you have a go:
0005A.
00Express 2.7 hrs
(decimal) into hours and minutes normal time?
0005B.
00Express 0.9 hrs
(decimal) into hours and minutes normal time?
|
Calculating the Distance:
There are 3 units
of distance Mile, kilometre and feet, however we are only concerned
with the first two. Miles and Kilometres must always be worked
out together and not mixed.
On you way to
a night club you average 50 miles / h and it takes 2 1/2 hours.
How far have you trevelled.
In one (1) hour
you travel 50 miles, so
in 2 1/2 hours
you travel 2.5 x 50 = 125 miles
You must remember
that you have to convert 2 1/2 into decimal time, but its a
good night club, so you don`t mind the distance.
|
|
Now you have a go:
0006A.
A driver
keeps a speed of 40 Kilometres on a journey that takes 000000000000001
hr and 45 minutes, how far did the driver travel?
0006B.
You spend
some time with your friends but it takes you 1 hr and 48 00000000000minutes
to get there, at an average speed of 65 miles hour, how
00000000000000000000000000 far
have you gone?
00006C.
During
a hill walking exercise in hilly Holland you climb a mountain
oooooooothat takes you 7 hrs 15
minutes to complete. You walk at an average 000000000speed
of 4 miles per hour, eating french bread sticks and drinking
000000000 wine made in spain by
the irish. What is the total distance covered 000000000000000of
your route and do you need new boots at the end?
|
|
Remember
Distance = Speed x Time.
|
|
|
Calculating the Speed:
Speed could mean
a couple of things, how fast you travel, how far in a given time
frame and even the rate of change of the distance covered. The
speed we use are miles per hour and kilometres per hour. Have
a look at this example:
On your holiday
route you stop off for a break after driving for 2 hours, you
also notice that you have covered 138 miles, what would be you
average speed for that part of the journey.
Distance = 138
Miles 0000000 Time
= 2 hours
In 2 hrs you travel
138 miles, so
in 1 hour your
average speed = 138
0000000000000000000000000--------
00000000000000000000000002
= 69 Miles
|
|
Now you have a go:
0 07A.
A driver
covers the distance of 48 miles on a journey that takes 000000000000001
hr and 30 minutes, what was the average speed?
0007B.
A cyclist
called Pete Rice spends 2 hrs and 42 minutes on the 000000000droad
and covers 42 mile, what was petes average speed?
|
|
Remember
Speed = Distance
oooooooooooooo
Time.
|
|
|
Calculating the Time:
For this sum, you
will need to understand the 24 hour clock, I have introduced you
to this clock, if you are unsure of the 24 hour clock, click
here.
We will go into
this head first, because its easy, try these:
08A.
A driver
leaves his house at 07.30 hrs and arrives at 11.50 hrs 0
dHow long was the journey?
08B.
A section
arrives at an RV at 21.39 hrs after marching for 3 hrs and 47
minutes. What time
did the patrol leave there base?
08C.
A Chopper
pilot takes off at 0957 hrs and flies for 1 hr and 17 minutes
before he lands. What time did he land?
|
|
Now that you understand the
3 sums, we are now going to put them all together to calculate
the distance, Speed and Time.However, once again. I will talk
you through the first one.
|
|
The distance to you friends
house is 90 miles and you usually average 60 miles / h on the
journey. How long does it take you to get there?
0000000000Distance
= 90 Miles / h000000
Speed = 60 Miles / h
So,
In 1 hour you
travel 60 miles ( 30 miles to go ) & in 1/2 an hour
you will travel
30 miles
This will
take you 1 hr and 30 minutes or 1.5 hours
Or,
write it as a fraction
90
-------
0000000000000.60 000=
0001.5 hrs.
|
|
Calculating Distance,Time
& Speed:
|
|
That is the Distance, Speed
and Time finished, now try the following quastions and remember
that all the answers are attached over the page,
click to see answers.
09A.
A Journey
home takes you 1 hr and 45 minutes. If you average 36
miles / h. What is the total distance?
09B.
Your friend
comes to visit, he checks the mileage when he arrives and calculates
that he has just travelled 56 miles in 1 hr and 36 minutes.
What
was his average speed.?
09C.
A car can
average a speed of 80 km /h on the motorway. If you rest after
3 hrs and 18 minutes. How far have you travelled.?
9D. A
person in a dutie Companycompletes his BFT (3 Mile) in a total
time of 24 minutes. What is his average speed.
|
|
|
If all else fails
then try and remember this, the magic triangle.
|
|
This triangle has
3 variables. The idea is that if you want to calculate speed,
cover up the S if you want to calulate distance cover up the D
and if calculating time, cover the T.
|
|
1. By covering the letter S
with your finger you will be able to calculate Speed.
SPEED 00=
00Distance divided by Time
2. By covering the letter D
with your finger you will be able to calculate Distance.
DISTANCE00=
00Speed 0x
0Time
3. By covering the letter T
with your finger you will be able to calculate Time.
TIME00=
00Distance divided
by Speed
|
|
| |
|
|
| |
