Question

1. Let ä = 4i +3j and b = 3 + 4. Find the magnitudes of (a) ā, (b) b, (c)ā +b and (d)ā -b.

JEE/Engineering Exams

Physics

Solution

118

4.0 (1 ratings)

( vec{a}=4 hat{u}+3 hat{g} ) ( vec{b}=3 hat{imath}+4 hat{g} ) a) ( |vec{a}|=sqrt{4^{2}+3^{2}}=sqrt{25}=5 ) b) ( |vec{b}|=sqrt{3^{2}+4^{2}}=sqrt{25}=5 ) c) ( |vec{a}+vec{b}|=(4 hat{imath}+3 hat{g})+(3 hat{imath}+4 hat{g}) ) ( =7 hat{imath}+7 hat{g} ) ( =sqrt{7^{2}+7^{2}}=sqrt{2 times 49}=7 sqrt{2} ) d) ( |vec{a}-vec{b}|=(4 hat{i}+3 hat{g})-(3 hat{imath}+4 hat{g}) ) ( =lambda-hat{q} quad=sqrt{1^{2}+(-1)^{2}}=sqrt{2} )