question_answer

A body of mass 5 kg under the action of constant force \[\overset{\to }{\mathop{F}}\,={{F}_{x}}\hat{i}+{{F}_{y}}\hat{j}\]has velocity at\[t=0s\]as\[\overset{\to }{\mathop{v}}\,=\left( 6\hat{i}-2\hat{j} \right)m/s\]and at t = 10s as \[\overset{\to }{\mathop{v}}\,=+6\hat{j}\,m/s.\] The force \[\overset{\to }{\mathop{F}}\,\]is: [JEE ONLINE 11-04-2014]

A) \[\left( -3\hat{j}+4\hat{j} \right)N\]

B) \[\left( -\frac{3}{5}\hat{i}+\frac{4}{5}\hat{j} \right)N\]

C) \[\left( 3\hat{i}-4\hat{j} \right)N\] 

D) \[\left( \frac{3}{5}\hat{i}-\frac{4}{5}\hat{j} \right)N\]