Using a metre scale, the length of the string of a simple pendulum is measured to be 90.0 cm . Measurements with a slide callipers determine the radius of the bob plus the length of the hook to be 2.13 cm . Determine the effective length of the pendulum. (The effective length is defined as the distance between the point of suspension and the centre of the bob.)

Step-by-step solution

The effective length of the pendulum is the sum of the length of the string and the radius of the bob plus the length of the hook. L = l₁ + l₂ Given l₁ = 90.0 cm and l₂ = 2.13 cm . L = 90.0 + 2.13 = 92.13 cm According to the rules of significant figures for addition, the final result must retain as many decimal places as there are in the number with the least decimal places. Since 90.0 has only one decimal place, the result must be rounded off to one decimal place. Therefore, the effective length is 92.1 cm .