TACHYMETER
(for models with tachymeter scale on the dial)
To measure the hourly average speed of a vehicle
U s e t h e s t o p w a t c h t o
1
determine how many seconds
it takes to go 1 km or 1 mile.
2
Ta c hyme ter s c ale indic a te d
by STOPWATCH second hand
gives the average speed per
hour.
l Tachymeter scale can be used only when the time required is less than 60 seconds.
Ex. 2: If the measuring distance is extended to 2 km or miles or shortened to 0.5 km or
miles and STOPWATCH second hand indicates "90" on tachymeter scale:
"90" (tachymeter scale figure) x 2 (km or mile) = 180 km/h or mph
"90" (tachymeter scale figure) x 0.5 (km or mile) = 45 km/h or mph
14
Ex. 1
STOPWATCH
second hand:
40 seconds
Tachymeter scale:
"90"
"90" (tachymeter scale figure) x 1 (km or mile)
= 90 km/h or mph
To measure the hourly rate of operation
Use the stopwatch to measure
1
the time required to complete 1
job.
2
Ta c hyme ter s c ale indic a te d
by STOPWATCH second hand
gives the average number of
jobs accomplished per hour.
Ex. 2: If 15 jobs are completed in 20 seconds:
"180" (tachymeter scale figure) x 15 jobs = 2700 jobs/hour
Ex. 1
STOPWATCH
second hand:
20 seconds
Tachymeter scale: "180"
"180" (tachymeter scale figure) x 1 job
= 180 jobs/hour
15