Answer: The focal length of the lens = 3.32 cm.
Explanation:
Lens formula : (i)
f= focal length , v=image distance , u =object distance.
magnification: m = (ii )
Given: v= -12.8 cm , m =2.85
Put values in (ii), we get
substitute values of u , v in (i)
Hence, the focal length of the lens = 3.32 cm.
According to the statement:
a) speed is equal to 118 km/h in kilometres per hour.
b) yes it is exceeding 90km/h.
<h3>What does speed mean?</h3>The pace at which an object's position changes in any direction is referred to as speed. Speed is defined as the ratio of something like the distance traversed to the time required to cover that distance. . . Speed is a scalar quantity since it just has a direction and no magnitude..
<h3>How are the speeds determined?</h3>Speed is determined by dividing the distance by the time. Calculating the units for speed requires knowledge of the units for both time and distance.. The units in this example will be meters per second (m/s), since the distance is measured in meters (m) and the time is measured in seconds (s).
(a)s₂= 118.km/h is its speed in kilometres per hour.
1h = 3600s
1km = 1000m
s₂= (33m/s) *
= 118.8km/h
s₂= 118.km/h
(b) yes it is exceeding 90km/h.
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