6. which of the following is true about sound? Sound is longitudinal wave 1. Sound is a transverse wave. Ill, Sound needs a medium to propagate. IV. Sound does not need a medium to propagate. Both I and IIt. Both I and IV. Both II and Ill. Both II and IV. All three , namely 1, II, and Iv. Height of a branch. Attached at the branch of a tree, a swing with a tire attached on the lower end was displaced so that it undergoes a simple harmonic motion. (See the figure below.) The period of oscillation is found to be is 5.67s. What is the approximate height of the tree? 7m. O 8m. O 9m. 10 m. The mass of the tire is needed. 8 On Earth, the period of a simple pendulum is 1.0 s. When brought to the Moon where g is one-sixth that on Earth, the period would be: 0.17 s, O 0.41 s. O 1.0 . O 245 O 6.0 s. 9 Which classroom would be noisier if densely populated by students post-pandemic scenario): ()) The one with concrete walls, no covering: (II) The one with concrete walls covered by thick curtains? Note: Choose the best answer. I only. O ti only. O Either I or II. O Both | and It. O Neither I nor II. 10. For a simple harmonic motion, where is the magnitude of the instantaneous acceleration maximum? At equilibrium position. At maximum displacement. At one half the maximum displacement. O At one-fourth the maximum displacement. At three-fourths the maximum displacement