Motion in a Straight Line - Result Question 14
14. A body is moving with velocity $30 m / s$ towards east. After 10 seconds its velocity becomes $40 m / s$ towards north. The average acceleration of the body is
(a) $1 m / s^{2}$
(b) $7 m / s^{2}$
(c) $7 m / s^{2}$
(d) $5 m / s^{2}$
[2011]
Show Answer
Answer:
Correct Answer: 14. (d)
Solution:
- (d) Average acceleration
$=\frac{\text{ Changein velocity }}{\text{ Total Time }}$
$=\frac{|40 \hat{j}-30 \hat{i}|}{10}$
$\langle a\rangle=\sqrt{4^{2}+(-3)^{2}}$
