Question

A man moves 20 m North, then 10 m East and then 10 $\sqrt{2}$ m South-West, his displacement is

• A. 20 m North
• B. 10 $\sqrt{2}$ m North-West
• C. 10 $\sqrt{2}$ m South-East
• D. 10 m North

Answer 1

Answer: (B)

10 $\sqrt{2}$ m North-West

Answer 2

$v=\frac{{{v}_{1}}+{{v}_{2}}}{2}$ $v=\frac{5\times {{10}^{6}}+2\times {{10}^{6}}}{2}=\frac{7}{2}\times {{10}^{6}}$ $d=v\times t$ $t=\frac{d}{v}=\frac{2.1\times {{10}^{-4}}\times {{10}^{-2}}}{\frac{7}{2}\times {{10}^{6}}}$ $t=6\times {{10}^{-13}}s$