Question

A body is projected horizontally with speed $20m{s}^{-1}$ . The speed of the body after $5s$ is nearly

• A. $54m{s}^{-1}$
• B. $35m{s}^{-1}$
• C. $20m{s}^{-1}$
• D. $70m{s}^{-1}$

Answer 1

Answer: (A)

$v_x=u=20m{s}^{-1}$
$v_y=v_u+gt$
$=0+10\times 5=50m{s}^{-1}$
$v=\sqrt{u_x^2+u_y^2}$
$=\sqrt{{\left(20\right)}^2+{\left(50\right)}^2}=54m{s}^{-1}$