An object is thrown horizontally from a point A from a tower and hits the ground 3 s later at B. The line from A to B makes an angle of 30° with the horizontal. The initial velocity of the object is: (take g = 10 m/s²)

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G1 Physics · Accepted Answer

For a horizontal projection, vertical drop after time t is y = ½gt² and horizontal displacement is x = ut. With t = 3 s and ∠AB with the horizontal = 30°, tan30° = y/x = (½gt²)/(ut) = gt/(2u). Thus u = gt/(2tan30°) = 15√3 m/s. This value is not present in the printed options; the source key marks option A (5√3 m/s), so the printed question/key is internally inconsistent.