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4-1.Newton's Laws of Motion
medium
An object of mass $2 \,kg$ at rest at origin starts moving under the action of a force $\vec{F}=\left(3 t^2 \hat{i}+4 \hat{j}\right) N$ The velocity of the object at $t=2 \,s$ will be ............. $m / s$
A$(3 \hat{i}+2 \hat{j})$
B$(2 \hat{i}+4 \hat{j})$
C$(4 \hat{i}+4 \hat{j})$
D$(3 \hat{i}-4 \hat{j})$
Solution
(c)
$\vec{F}=3 t^2 \hat{i}+4 \hat{j}$
$P_2-P_1=\frac{3 t^3}{3} \hat{i}+\frac{4 t^2}{2} \hat{j}$
$P_1=0$
$(2) v=(2)^3 \hat{i}+2(2)^2 \hat{j}$
$v=4 \hat{i}+4 \hat{j}$
$\vec{F}=3 t^2 \hat{i}+4 \hat{j}$
$P_2-P_1=\frac{3 t^3}{3} \hat{i}+\frac{4 t^2}{2} \hat{j}$
$P_1=0$
$(2) v=(2)^3 \hat{i}+2(2)^2 \hat{j}$
$v=4 \hat{i}+4 \hat{j}$
Standard 11
Physics
