Question 89: Work, Energy and Power & Circular Motion

Question

A person moved from A to B on a circular path as shown in figure. If the distance travelled by him is $$60 \mathrm{~m}$$, then the magnitude of displacement would be :
(Given $$\left.\cos 135^{\circ}=-0.7\right)$$

Accepted Answer

Distance travelled = 60 m
$$\Rightarrow$$ Angle covered = 135$$^\circ$$
Displacement $$ = 2R\sin \left( {{{135^\circ } \over 2}} ight)$$
$$ = 2\left( {{{60} \over {135}} 	imes {{180} \over \pi }} ight){\left[ {{{1 - \cos (135^\circ )} \over 2}} ight]^{1/2}}$$
$$ = 2\left( {{{80} \over \pi }} ight){(0.85)^{1/2}}$$
$$ \approx 47$$ m

Answer

42 m

Answer

47 m

Answer

19 m

Answer

40 m

Work, Energy and Power & Circular Motion

A person moved from A to B on a circular path as shown in figure. If the distance travelled by him is $60 \mathrm{~m}, then the magnitude of displacement would be : (Given \left.\cos 135^{\circ}=-0.7\right)

Choose the correct answer: