Page 47 - Physics

Measurement

Measurement of ti me happens. Under normal circumstances,

Time is a measure of the interval between time is usually measured using a clock or
two events, or the period within which an a wristwatch shown in Figures 2.19(a) and
event takes place. It is the precise moment (b), respectively.
as determined by a clock or a watch. The
SI unit of time is second (s). There are
smaller units of time that are based on the
second. These are the millisecond (ms), the
microsecond (μs), and the nanosecond (ns)
shown in Table 2.5.
Large units of time are minutes, hours,
days, weeks, months and years shown in
Table 2.6. (a) Clock

Table 2.5: Small units of time
Time Comparison with
SI unit
1 millisecond (ms) 1

1 000 s (b) Wristwatch
1 microsecond 1
(µs) 1 000 000 s Figure 2.19: A clock and wristwatch

1 nanosecond (ns) 1 For those experiments that require
1 000 000 000 s measurement of time in the laboratory,
stopwatches are used. At this level, we

Table 2.6: Large units of time shall concentrate on measuring time by
using a stopwatch.
Time Comparison with SI unit

1 day ( 24 × 60 × 60) s A stopwatch is a device that is held in the
hand and is used to show the time elapsed.
1 hour (hr) ( 60 × 60) s Thus, the time interval is obtained from
the moment the stopwatch is started to the
1 minute (min) 60 s
moment it is stopped. A stopwatch is used
when time must be measured precisely and
Reading ti me using stopwatch with a minimum error. Stopwatches are
Time is used to indicate when an event used for timing laboratory experiments or
occurs, the order in which several events sporting activities such as athletics.
occurs or the rate at which an event

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Physics Form 1 Final.indd 41 16/10/2024 20:55