Question

Q13:- A ball is thrown vert ically upward from the gro and with an initial spee d of 15 m/s Determine the velocity of the ball at t- 1s. (A) 1ms-1 (B)2ms1 (C)3ms-1 (D)4m s-1 (E) 51ns-1 (214:-At what angle to the stadium() ground a footbal I is kicked (S). If it r eached a rnaximum height of (10 m), and a maximum horizontal dis tance of (60 m )? (A) 45(B) 26.6 (C) 53.1 (D) 33.7 (E) 38.6

Answer 1

$v=u-gt$

$v=15-10\times 1=5\textup{ m/s}$

$H=\frac{u^2\sin^2\theta}{2g},\quad R=\frac{u^2\sin2\theta}{g}$

$\frac{R}{H}=\frac{2\sin2\theta}{\sin^2\theta}=\frac{4}{\tan\theta}$

Given to us

$\frac{R}{H}=6$

Thus,

$\tan\theta=\frac{2}{3}$

$\theta=\tan^{-1}\frac{2}{3}$

which is approximately,

$\theta=33.7\degree$