Question 57

A balloon leaves from a point P rises at a uniform speed. After 6 minutes, an observer situated at a distance of $$450\surd3$$ metres from point P observes that angle of elevation of the balloon is 60°. Assume that point of observation and point P are on the same level. What is the speed (in m/s) of the balloon?

Solution

So, $$\frac{PB}{450\sqrt{3}}=\tan60^{\circ\ }.$$

or, $$PB=1350\ meter\ .$$

So, Speed of balloon = $$\frac{1350}{60\times6}\ \frac{meter}{\sec}=3.75\ \frac{meter}{\sec}\ .$$

B is correct choice.

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