Question

A particle has an initial velocity of $3\hat{i}+4\hat{j}$ and an acceleration of $0.3\hat{i}+0.4\hat{j}$. What is its speed after $10s$:

• A. $10units$
• B. $8.5units$
• C. $7\sqrt{2}units$
• D. $7units$

Answer 1

Answer: (A)

$10units$

v=u+at

$v=(3\hat{i}+4\hat{j})+(0.3\hat{i}+0.4\hat{j})10=(6\hat{i}+8\hat{j})$

$v=\sqrt{6^2+8^2}=10$ units