Question

11. From a certaln tower of unknown height it is found that the maximum range at a certain projection velocily, is obtained for a projection angle of 30 and this range is 10 projection velocity must be (A) 10 m/s m. The (B) 10-3 m/s (D) 5 m/s. 10 (C) m/s

Answer 1

Given, the maximum range is R_max = 10 squareroot 3 m the angle of projection for R_max, theta_m = 30 degree Because the range is given by R = u^2 sin 2 theta/g, where u: projection velocity Here, R_max = u^3/g sin 2 theta_m u^2 = g R_max/sin 2 theta u^2 = 10 times 10 - 3/sin 60 degree [assuming g = 10 m/s] u = squareroot 10 times 10 squareroot 3 times 2/squareroot 3 u = 10 squareroot 2 m/s The doesn't answer that is matching is 10 squareroot 3 m/s Therefore option (B) is correct.