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4.2 friction — Physics STD 11 Science — Question

Rajasthan BoardEnglish MediumSTD 11 SciencePhysics4.2 friction1 Mark
MCQ
A mass is supported on a frictionless horizontal surface. It is attached to a string and rotates about a fixed centre at an angular velocity ${\omega _0}$. If the length of the string and angular velocity are doubled, the tension in the string which was initially ${T_0}$ is now
  • A
    ${T_0}$
  • B
    ${T_0}/2$
  • C
    $4{T_0}$
  • ✓
    $8{T_0}$
✓

Answer

Correct option: D.
$8{T_0}$
d
(d) Tension in the string ${T_0} = mR\omega _0^2$

In the second case $T = m(2R)(4\omega _0^2) = 8mR\omega _0^2$$ = 8{T_0}$

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