Physics Two Dimensional Motion Question 160
Question: A bullet is fired with a speed of $ 1500m\text{/}s $ in order to hit a target 100 m away. If $ g=10m\text{/}s^{2}. $ The gun should be aimed
Options:
A) 15 cm above the target B) 10 cm above the target C) 2.2 cm above the target D) directly towards the target
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Answer:
Correct Answer: C
Solution:
[c] The bullet performs a horizontal journey of 100 cm with constant velocity of 1500 m/s. The bullet also performs a vertical journey of h with zero initial velocity and downward acceleration g. $ \
Therefore $ For horizontal journey, $ \text{time }( \text{t} )=\frac{\text{Distance}}{\text{Velocity}} $ $ \
Therefore ,,,t=\frac{100}{1500}=\frac{1}{15}\text{sec }…\text{(1)} $ The bullet performs vertical journey for this time. For vertical journey, $ \text{h},\text{=},\text{ut+}\frac{\text{1}}{\text{2}}\text{g}{{\text{t}}^{\text{2}}} $ $ \text{h=0+}\frac{1}{2}\times 10\times {{( \frac{1}{15} )}^{2}} $ $ \text{or, h=}\frac{20}{9}\text{ cm = 2}\text{.2cm} $
BETA
