Question

A particle is projected with velocity $u$ inclined at an angle $\alpha$ with $x-axis$. Change in velocity of the particle on return to ground is

• A. $zero$
• B. $2 \,u$
• C. $2u \,cos\, \alpha$
• D. $2u \,sin\,\alpha$

Answer 1

Answer: (D)

$2u \,sin\,\alpha$

Answer 2

Initial velocity along y axis = u sin $\alpha$ Final velocity along y axis = - u sin $\alpha$ Change in velocity = u sin $\alpha$ - $(-u\,sin\,\alpha)$ = $2\,u\,sin\,\alpha$