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3-2.Motion in Plane
hard
A projectile is thrown with velocity $U=20\ m/s ± 5\%$ at an angle $60^o.$ If the projectile falls back on the ground at the same level then ......... $m$ of following can not be a possible answer for range.
A
$39.0$
B
$37.5$
C
$34.6$
D
$32.0$
Solution
$\mathrm{R}=\frac{20^{2} \times \sin 120^{\circ}}{\mathrm{g}}=20 \sqrt{3}=\frac{\Delta \mathrm{R}}{\mathrm{R}}=\frac{24 \mathrm{U}}{\mathrm{U}}$
$\Rightarrow \Delta \mathrm{R}=\frac{2 \times 5}{100} \times 200 \sqrt{3}=2 \sqrt{3}$
$20 \sqrt{3}-2 \sqrt{3}<\mathrm{R}<20 \sqrt{3}+2 \sqrt{3}$
$\Rightarrow 31.1 \mathrm{m}<\mathrm{R}<38.1 \mathrm{m}$
Standard 11
Physics
