The radius of the circle is 3.12 m. Calculate the area of the circle with regard to significant figures.

The measurement value of length of a simple pendulum is 20cm known with 2mm accuracy. The time for 50 oscillations was measured to be 40 s within is resolution. Calculate the percentage accuracy in the determination of acceleration due to gravity 'g' from the above measurement.

Show that a screw gauge of pitch 1mm and 100 divisions is more precise than a vernier caliper with 20 divisions on the sliding scale.

Having all units in atomic standards is more useful. Explain.

From a point on the ground, the top of a tree is seen to have an angle of elevation 60^o . The distance between the tree and a point is 50m. calculate the height of the tree?