A student has a stack of 20 identical coins.
Figure shows the student measuring the height of the stack using a ruler.
(a) With his eye at the position shown, the student's measurement of the height of the stack is 6.8 cm.
Suggest two reasons why the student's measurement is inaccurate.
(b) Another student correctly determines the height of the stack as 7.7 cm.
Calculate the average thickness of one coin.
(c) The mass of a single coin is 12 g.
State this mass in kg.
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a) i) Height should be measured with same horizontal line
ii) Angle btw the object and eye should be zero
b) Height
no. of coins
So average height of coin is
average height
(c) mass of coin = 12 g
mass in kg
= 0.012 kg