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3-1.Vectors
medium
A person pushes a box kept on a horizontal surface with force of $100\,N$ . In unit vector notation force $\vec F$ can be expressed as ?
A
$100\,(\hat i + \hat j)$
B
$100\,(\hat i - \hat j)$
C
$50\sqrt 2\,(\hat i - \hat j)$
D
$50\sqrt 2\,(\hat i + \hat j)$
Solution
$\overrightarrow{\mathrm{F}} =\mathrm{Fcos}\left(-45^{\circ}\right) \hat{\mathrm{i}}+\mathrm{F} \sin \left(-45^{\circ}\right) \hat{\mathrm{j}}$
$=\frac{\mathrm{F}}{\sqrt{2}}(\hat{\mathrm{i}}-\hat{\mathrm{j}})=50 \sqrt{2}(\hat{\mathrm{i}}-\hat{\mathrm{j}})$
Standard 11
Physics
