JEE Mains · Physics · STD 11 - Vectors
- JEE Mains 2022
- Hard
- Numerical
A person moved from \(A\) to \(B\) on a circular path as shown in figure. If the distance travelled by him is \(60 \,m\), then the magnitude of displacement would be\(.....\,m\) (Given \(\left.\cos 135^{\circ}=-0.7\right)\)

Pick an option to check your answer.
Answer & Solution
Correct Answer
(B) \(47\)
Step-by-step Solution
Detailed explanation
\(d = R \theta\)
\(60= R \left(\frac{3 \pi}{4}\right)\)
\(R =\frac{60 \times 4}{3 \pi}=\frac{80}{\pi} m\)
Displacement \(=\sqrt{ R ^{2}+ R ^{2}-2 R ^{2} \cos 135}\)
\(\Rightarrow \sqrt{2 R ^{2}-2 R ^{2}(-0.7)}\)
\(\Rightarrow \sqrt{3.4 R ^{2}}=\sqrt{3.4\left(\frac{80}{\pi}\right)^{2}}\)
\(\approx 47\,m\)
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