Four balls of mass 5 kg each are placed on the top of a horizontal turntable and fastened together with four strings of length 1 m each to from a square of side 1m. The axis of rotation passes through the centre of the square. Find the tension in the strings when the turntable is rotated at the rate of `(30)/(pi)` rpm.

Explanation

In the table is shown from the top. When the turntable keeps on rotating, the centrifugal force experienced by each ball will be `m omega^(2)`r.
Here, m = 5 kg, `omega = 2pi xx (30)/(pi xx 60) = 1 "rad"cdot s^(-1)`
As the length of each side of the square is 1 m,
r = `(1)/(2)xx` length of the diagonal or, `r = (sqrt(2))/(2) = (1)/(sqrt(2))` m
According to the figure, tension is each string,
T = `m omega^(2) r cos 45^(@) = 5 xx (1)^(2) xx (1)/(sqrt(2)) xx (1)/(sqrt(2)) = (5)/(2) = 2.5` N.