Kinematics Question 642
Question: Two particles are projected simultaneously from the level ground . They may collide after a time:
Options:
A) $ \frac{x\sin {\theta _{2}} _{}}{u _{1}} $
B)$ \frac{x\text{ cos}{\theta _{2}} _{}}{u _{2}} $
C) $ \frac{x\sin {\theta _{2}} _{}}{u _{1}\sin ( {\theta _{2}}-{\theta _{1}} )} $
D)$ \frac{x\sin {\theta _{1}} _{}}{u _{2}\sin ( {\theta _{2}}-{\theta _{1}} )} $
Show Answer
Answer:
Correct Answer: C
Solution:
[c] $ x+u _{2}\cos {\theta _{2}}t=u _{1}\cos {\theta _{1}}t $
$ \therefore t=\frac{x}{u _{1}\cos {\theta _{1}}-u _{2}\cos {\theta _{2}}} $ -(i)
Also $ u _{1}\sin {\theta _{1}}=u _{2}\sin {\theta _{2}} $ -(ii)
After solving above equations, we get
t= $\frac {x\sin {\theta _{2}}} {u{ _{1}}\sin ( {\theta _{2}}-{\theta _{1}} )} $
