Question 472: Centre of Mass and Rotational Motion

Question

A body of mass m = 10 kg is attached to one
end of a wire of length 0.3 m. The maximum
angular speed (in rad s–1) with which it can be
rotated about its other end in space station is :
(Breaking stress of wire = 4.8 × 107 Nm–2 and
area of cross-section of the wire = 10–2 cm2) is:

Accepted Answer

T = m$${\omega ^2}l$$
Breaking stress = $$\sigma $$ = $${{m{\omega ^2}l} \over A}$$
$$ \Rightarrow $$ $${\omega ^2}$$ = $${{4.8 	imes {{10}^7} 	imes \left( {{{10}^{ - 2}} 	imes {{10}^{ - 4}}} ight)} \over {10 	imes 0.3}}$$ = 16
$$ \Rightarrow $$ $$\omega $$ = 4

Centre of Mass and Rotational Motion

A body of mass m = 10 kg is attached to one end of a wire of length 0.3 m. The maximum angular speed (in rad s–1) with which it can be rotated about its other end in space station is : (Breaking stress of wire = 4.8 × 107 Nm–2 and area of cross-section of the wire = 10–2 cm2) is:

Choose the correct answer: