Motion In A Straight Line Ques 8
8. 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
[2011]
(a) $1 $ $m / s^{2}$
(b) $7 $ $ m / s^{2}$
(c) $7 $ $m / s^{2}$
(d) $5$ $ m / s^{2}$
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Answer:
Correct Answer: 8.(d)
Solution:
- (d) Average acceleration
$< a >=\frac{\text{ Change in velocity }}{\text{ Total Time }}$
$< a >=\frac{|40 \hat{j}-30 \hat{i}|}{10}$
$< a > =\sqrt{4^{2}+(-3)^{2}}$
$< a >=5 m / s^{2}$
BETA
