Question

a football is thrown upward with an angle of 30 degree with respect to the horizontal to through a 40 m pass what must be the initial speed of balls​

Answer 1

Answer:

15

Explanation:

Answer 2

$\tt {\pink{Given}}\begin{cases} \sf{\green{Range \: (R)=40 \: m}}\\ \sf{\blue{\theta=30^{\circ}}}\\ \sf{\orange{v_i= \: ?}}\end{cases}$

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Answer:

$:\implies \sf Range = \dfrac{{v_i}^2 \: sin \: 2 (\theta)}{g}$

$:\implies \sf 40= \dfrac{{v_i}^2 \: sin \: 2 \:(30^{ \circ}) }{9.8}$

$:\implies \sf 40 \times 9.8= {v_i}^2 \: sin \: 60^{ \circ}$

$:\implies \sf 392= {v_i}^2 \times \dfrac{ \sqrt{3} }{2}$

$:\implies \sf 392= {v_i}^2 \times \dfrac{ 1.732 }{2}$

$:\implies \sf 392= {v_i}^2 \times 0.866$

$:\implies \sf {v_i}^2 = \dfrac{392}{0.866}$

$:\implies \sf {v_i}^2 = 452.64$

$:\implies \underline{ \boxed{ \textsf{\textbf {v _i = 21.2 ms ^{ - 1} }}}}$

$\therefore\underline{\textsf{ The initial speed of the ball is \textbf{21.2 ms ^{-1} }}}$