NEET · Physics · STD 11 - 3.2 motion in plane
The angular speed of a flywheel is increased from 600 rpm to 1200 rpm in 10 s. The number of revolutions completed by the flywheel during this time is :
- A 900
- B 600
- C 150
- D 300
Answer & Solution
Correct Answer
(C) 150
Step-by-step Solution
Detailed explanation
(C) 150
Initial angular speed, \(\omega_0=\frac{600 \times 2 \pi}{60}=20 \pi\ rad / s\)
Final angular speed, \(\omega=\frac{1200 \times 2 \pi}{60}=40 \pi\ rad / s\)
Angular acceleration, \(\alpha=\frac{\omega-\omega_0}{t}=\frac{40 \pi-20 \pi}{10}=2 \pi\ rad / s ^2\)
Angular displacement, \(\theta=\omega_0 t+\frac{1}{2} \alpha t^2\)
\(\theta=20 \pi \times 10+\frac{1}{2} \times 2 \pi \times(10)^2=200 \pi+100 \pi=300 \pi\ rad\)
Number of revolutions, \(N=\frac{\theta}{2 \pi}=\frac{300 \pi}{2 \pi}=150\)
Initial angular speed, \(\omega_0=\frac{600 \times 2 \pi}{60}=20 \pi\ rad / s\)
Final angular speed, \(\omega=\frac{1200 \times 2 \pi}{60}=40 \pi\ rad / s\)
Angular acceleration, \(\alpha=\frac{\omega-\omega_0}{t}=\frac{40 \pi-20 \pi}{10}=2 \pi\ rad / s ^2\)
Angular displacement, \(\theta=\omega_0 t+\frac{1}{2} \alpha t^2\)
\(\theta=20 \pi \times 10+\frac{1}{2} \times 2 \pi \times(10)^2=200 \pi+100 \pi=300 \pi\ rad\)
Number of revolutions, \(N=\frac{\theta}{2 \pi}=\frac{300 \pi}{2 \pi}=150\)
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
- Three identical spheres, each of mass \(M ,\) are placed at the corners of a right angle triangle with mutually perpendicular sides equal to \(2 \;m\) (see figure). Taking the point of intersection of the two mutually perpendicular sides as the origin, find the position vector of centre of mass.
NEET 2020 Medium - A 100-turn closely wound circular coil of radius 5 cm has a magnetic field of \(3.14 \times 10^{-3}\) T at its centre. The current flowing through the coil, and the magnitude of the magnetic moment of this coil are, respectively :
(Take \(\mu_0=4 \pi \times 10^{-7} T m / A\) )NEET 2026 Hard - The radius of inner most orbit of hydrogen atom is \(5.3 \times 10^{-11}\,m\).\(........\mathring A\) is the radius of third allowed orbit of hydrogen atom.NEET 2023 Easy
- The power of a biconvex lens is \(10\) dioptre and the radius of curvature of each surface is \(10 \;cm\). Then the refractive index of the material of the lens is,NEET 2020 Medium
- Three liquids of densities \(\rho _1,\rho _2\) and \(\rho _3\) (with \(\rho _1 > \rho _2 > \rho_3),\) having the same value of surface tension \(T,\) rise to the same height in three identical capillaries. The angles of contact \(\theta_1 \,,\theta_2\) and \(\theta_3\) obeyNEET 2016 Medium
- If the magnitude of sum of two vectors is equal to the magnitude of difference of the two vectors, the angle between these vectors is ........ \(^o\)NEET 2016 Medium
More PYQs from NEET
- The stability of \(Cu ^{2+}\) is more than \(Cu ^{+}\)salts in aqueous solution due to -NEET 2023 Medium
- Match List \(I\) with List \(II\)
Choose the correct answer from the options given below:List \(I\) List \(II\) \(A\). Rhizopus \(I\). Mushroom \(B\). Ustilago \(II\). Smut fungus \(C\). Puccinia \(III\). Bread mould \(D\). Agaricus \(IV\). Rust fungus NEET 2024 Medium - Activation energy of any chemical reaction can be calculated if one knows the value ofNEET 2024 Medium
- The chronological order of human evolution from early to the recent isNEET 2016 Easy
- Noble gases are named because of their inertness towards reactivity. Identify an incorrect statement about them.NEET 2021 Hard
- Identify the correct statements about biomolecules.
A. Lipids are generally water soluble.
B. Proteins are polypeptides.
C. Polysaccharides are long chains of sugars.
D. Adenine and guanine are substituted pyrimidines.
E. Almost all enzymes are proteins.
Choose the correct answer from the options given below :NEET 2026 Easy