Question

A body is projected with a velocity 6i +8j + 20k . i , j being
in horizontal plane and in vertical plane. Horizontal range of the
body is (take g=10ms?)
(A) 80m
(B) 20m
(C) 40m
(D) 34m​

Answer 1

Answer:

20m....... is correct answer....

Answer 2

$\vec{v}=6\hat{i}+8\hat{j}$

Comparing with $\vec{v}$

$=v_x \hat{i}+v_y \hat {j}$, we get

$v_x=6ms^{-1}$ and $v_y=8ms^{-1}$

Also, $v^2=v_x^2 +v_y^2$

$=36+64=100$

or $v=10ms^{-1}$

$sin \theta =\frac{8}{10}$ and $cos \theta =\frac{6}{10}$

$R=\frac{v^2 sin 2\theta}{g}$ = $R=\frac{2v^2 sin\theta cos \theta}{g}$

$R=2\times 10\times 10\times \frac{8}{10}\times \frac{6}{10}\times \frac{1}{10}$

$=9.6m$

#SPJ3