gravity =9.8m/s

A string fixed at both ends resonates at a fundamental frequency of 180 Hz. Which of the following will reduce the fundamental frequency to 90 Hz? O Halve the tension and keep the length fixed Keep the tension fixed and double the length Keep the tension fixed and halve the length Double the tension and double the length 1 point Three identical bodies of mass M are located at the vertices of an equilateral triangle of side L. They revolve under the effect of mutual gravitational force in a circular orbit, circumscribing the triangle while preserving the equilateral triangle. Their orbital velocity is: 3 GM 2 GM 2L 3L O Option 3 O Option 4 3 GM GM L L O Option 2 O Option 1