Question

A body is moving with velocity $30\, ms$ towards east After 10 s its velocity becomes $40 \,ms$ towards north. The average acceleration of the body is

• A. $7\, ms^{-1}$
• B. $\sqrt{7}\,ms^{-1}$
• C. $5\,ms^{-1}$
• D. $1 \,ms^{-2}$

Answer 1

Answer: (C)

Average acceleration
$\vec{ A }_{\text {avg }}=\frac{\vec{ v }_{ f }-\vec{ v }_{ i }}{ t }=\frac{40 \,\hat{ j }-30 \,\hat{ i }}{10} $
$\vec{ A }_{\text {avg }}=\frac{\sqrt{40^{2}+30^{2}}}{10}=5 \,m / \,sec ^{2}$