Question

An aeroplane is moving with a horizontal velocity u at a height h. The velocity of packet dropped from it on the earths surface will be:

• A. $ \sqrt{{{u}^{2}}-2\,gh} $
• B. $ 2\,gh $
• C. $ \sqrt{2\,gh} $
• D. $ \sqrt{{{u}^{2}}+2\,gh} $

Answer 1

Answer: (D)

Since, velocity is vector quantity, its horizontal component is $ u $ and vertical component is v and from equation of motion
$ v=\sqrt{2\,gh} $
Taking the resultant of $ u $ and $ v $
$ R=\sqrt{{{u}^{2}}+{{v}^{2}}} $
$ =\sqrt{{{u}^{2}}+2\,gh} $