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: (. Given . cos 135°=-0.7)

Question

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: (. Given . cos 135°=-0.7) (A) 42 m (B) 47 m (C) 19 m (D) 40 m

Tardigrade Admin · Accepted Answer

d = R θ 60= R ((3 π/4)) R =(60 × 4/3 π)=(80/π) m Displacement =√ R 2+ R 2-2 R 2 cos 135 ⇒ √2 R 2-2 R 2(-0.7) ⇒ √3.4 R 2=√3.4((80/π))2 ≈ 47 m

Q. 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 : $($ Given $cos 13 5^{\circ} = - 0.7)$

42 m

47 m

19 m

40 m

$d = Rθ$
$60 = R (\frac{3 π}{4})$
$R = \frac{60 \times 4}{3 π} = \frac{80}{π} m$
Displacement $= R^{2} + R^{2} - 2 R^{2} cos 135$
$\Rightarrow 2 R^{2} - 2 R^{2} (- 0.7)$
$\Rightarrow 3.4 R^{2} = 3.4 (\frac{80}{π})^{2}$
$\approx 47 m$

Q. A person moved from A to B on a circular path as shown in figure. If the distance travelled by him is 60m, then the magnitude of displacement would be : ( Given cos135∘=−0.7)