MHT CET · Physics · Rotational Motion
A disc of radius 0.4 meter and mass \(1 \mathrm{~kg}\) rotates about an axis passing through its center and perpendicular to its plane. The angular acceleration is \(10 \mathrm{rad} \mathrm{s}^{-2}\). The tangential force applied to the rim of the disc is
- A \(2 \mathrm{~N}\)
- B \(3 \mathrm{~N}\)
- C \(4 \mathrm{~N}\)
- D \(5 \mathrm{~N}\)
Answer & Solution
Correct Answer
(A) \(2 \mathrm{~N}\)
Step-by-step Solution
Detailed explanation
\(\mathrm{R}=0.4 \mathrm{~m}, \mathrm{M}=1 \mathrm{~kg}, \alpha=10 \mathrm{rad} / \mathrm{s}^2\)
\(\mathrm{I}=\frac{\mathrm{MR}^2}{2}=\frac{1 \times(0.4)^2}{2}=0.08 \mathrm{~kg} \mathrm{~m}^2\)
Torque, \(\tau=\mathrm{I} \alpha=0.08 \times 10=0.8 \mathrm{~N}-\mathrm{m}\)
Also, \(\tau=\) FR
or \(F=\frac{\tau}{R}=\frac{0.8}{0.4}=2 \mathrm{~N}\)
\(\mathrm{I}=\frac{\mathrm{MR}^2}{2}=\frac{1 \times(0.4)^2}{2}=0.08 \mathrm{~kg} \mathrm{~m}^2\)
Torque, \(\tau=\mathrm{I} \alpha=0.08 \times 10=0.8 \mathrm{~N}-\mathrm{m}\)
Also, \(\tau=\) FR
or \(F=\frac{\tau}{R}=\frac{0.8}{0.4}=2 \mathrm{~N}\)
See the Complete Solution
Get step-by-step explanations for this and 2.5 Lakh+ more JEE, NEET & CET questions.
- Unlock all solutions
- Practice the full chapter
- Track accuracy across PYQs
4.8 rated on Google Play · 14,000+ reviews
More questions from Physics
- A sphere of mass \(m\) moving with velocity \(v\) collides head-on another sphere of same mass which is at rest. The ratio of final velocity of the second sphere to the initial velocity of the first sphere is ( \(e\) is the coefficient of restitution and collision is inelastic)MHT CET 2018 Medium
- A current of \(5 \mathrm{~A}\) is flowing at \(220 \mathrm{~V}\) in the primary coil of transformer. If the voltage produced in the secondary coil is \(2200 \mathrm{~V}\) and \(50 \%\) of power is lost, then the current in secondary will beMHT CET 2022 Easy
- I - V characteristics of photodiode for different illumination intensities \(\mathrm{I}_1, \mathrm{I}_2, \mathrm{I}_3\) and \(\mathrm{I}_4\) are drawn as follows. Then the maximum intensity among them is
MHT CET 2025 Easy - The ratio of longest to shortest wavelength emitted in Paschen series of hydrogen atom isMHT CET 2023 Medium
- The frequency of radio waves corresponding to a wavelength of \(10 \mathrm{~m}\) isMHT CET 2012 Medium
- The magnetic field at a point \(\mathrm{P}\) situated at perpendicular distance ' \(R\) ' from a long straight wire carrying a current of \(12 \mathrm{~A}\) is \(3 \times 10^{-5} \mathrm{~Wb} / \mathrm{m}^2\). The value of ' \(R\) ' in \(\mathrm{mm}\) is \(\left[\mu_0=4 \pi \times 10^{-7} \mathrm{~Wb} / \mathrm{Am}\right]\)MHT CET 2023 Medium
More PYQs from MHT CET
- The CORRECT match isMHT CET 2014 Hard
- Which of the following is NOT a character of open circulation?MHT CET 2021 Medium
- The ratio of energies of photons produced due to transition of electron of hydrogen atom from its (i) second to first energy level and (ii) highest energy level to second energy level isMHT CET 2021 Hard
- The equation of line passing through and perpendicular to the lines and isMHT CET 2018 Easy
- The angle of deviation produced by a thin prism when placed in air is ' \(\delta_1\) ' and that when immersed in water is ' \(\delta_2\) '. The refractive index of glass and water are \(\frac{3}{2}\) and \(\frac{4}{3}\) respectively. The ratio \(\delta_1: \delta_2\) isMHT CET 2023 Medium
- Calculate current in ampere required to deposit \(4.8 \mathrm{~g} \mathrm{Cu}\) from it's salt solution in 30 minutes. \(\left[\right.\) Molar mass of \(\left.\mathrm{Cu}=63.5 \mathrm{~g} \mathrm{~mol}^{-1}\right]\)MHT CET 2023 Medium