Question

Aryan drops a ball from a hot air balloon flying at a height of 75 m. If the balloon is moving upwards with uniform velocity of 10 m/s, find the height of the balloon when the ball hits the ground. Take ($g=10m{s}^{-2}$ )

• A. 125 m
• B. 135 m
• C. 115 m
• D. 105 m

Answer 1

Answer: (A)

.Given Data:

Height of ball before falling from hot air balloon, $h=75m$

Initial velocity of ball, $u=10m{s}^{-1}$

Final velocity, $v=0{ms}^{-1}$

Distance covered from A to B=$xmeter$

$v^2-u^2=2as$

$0-10^2=2(-10)x$

$x=5m$

From B to ground height covered by ball,

$=x+h+x=2x+h⟹2\times 5+75=85m$

A