Question

A paraglider to show his skills jumped from a very tall building. After $2s$ of free fall he sees a balloon rising with constant speed of $2m{s}^{-1}$ at a distance $2m$ as shown. The relative angular velocity of balloon w.r.t person at this instant will be

• A. $10rad{s}^{-1}$
• B. $11rad{s}^{-1}$
• C. $12rad{s}^{-1}$
• D. $13rad{s}^{-1}$

Answer 1

The correct option is A $10rad{s}^{-1}$

Using first equation of motion,

$v=u+at$

$v=10\times 2=20m/s$

Relative velocity of balloon wrt the paraglider is:

$v_r=20+2=22m/s$

$r\omega =22$

$\omega =22/2=11rad{s}^{-1}$