Physics Two Dimensional Motion Question 184
Question: An object is projected with a velocity of $ 20m/s $ making an angle of $ 45{}^\circ $ with horizontal. The equation for the trajectory is $ h=Ax-Bx^{2} $ where h is height, x is horizontal distance, A and B are constants. The ratio A: B is $ ( \text{g = 10 m}{{\text{s}}^{-2}} ) $
Options:
A) $ 1:5 $ B)$ 5:1~~ $ C) $ 1:40 $ D)$ 40:1 $
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Answer:
Correct Answer: D
Solution:
[d] Given $ h=Ax-\text{B}{{\text{x}}^{\text{2}}} $ , on comparing with $ y=\text{x}\tan \theta -\frac{gx^{2}}{2u^{2}{{\cos }^{2}}\theta } $ , we get $ A=\tan \theta =tan45{}^\circ =1, $ and $ \text{B},,\text{=}\frac{g}{2u^{2}{{\cos }^{2}}\theta }=\frac{10}{2\times 20^{2}\times {{\cos }^{2}}45{}^\circ }=\frac{1}{40} $
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Therefore ,,,,\frac{\text{A}}{\text{B}}=40. $
BETA
