MHT CET · Physics · Motion In One Dimension
A ball kept at \(20 \mathrm{~m}\) height falls freely in vertically downward direction and hits the ground. The coefficient of restitution is \(0.4\). Velocity of the ball first rebound is \(\left[\mathrm{g}=10 \mathrm{~ms}^{-2}\right]\)
- A \(4 \mathrm{~ms}^{-1}\)
- B \(8 \mathrm{~ms}^{-1}\)
- C \(12 \mathrm{~ms}^{-1}\)
- D \(16 \mathrm{~ms}^{-1}\)
Answer & Solution
Correct Answer
(B) \(8 \mathrm{~ms}^{-1}\)
Step-by-step Solution
Detailed explanation
\(\begin{aligned}
v^2 & =0+2 g h \quad \ldots\left(\because v^2-u^2=2 g h\right) \\
& v^2=2 \times 10 \times 20=400 \\
& v=20 \mathrm{~m} / \mathrm{s} \\
& \mathrm{e}=\frac{\mathrm{u}}{\mathrm{v}}
\end{aligned}\)
\(\therefore \quad\) The velocity of the body after the first rebound is
\(\begin{aligned}
& u=0.4 \times 20 \\
& u=8 \mathrm{~m} / \mathrm{s}
\end{aligned}\)
v^2 & =0+2 g h \quad \ldots\left(\because v^2-u^2=2 g h\right) \\
& v^2=2 \times 10 \times 20=400 \\
& v=20 \mathrm{~m} / \mathrm{s} \\
& \mathrm{e}=\frac{\mathrm{u}}{\mathrm{v}}
\end{aligned}\)
\(\therefore \quad\) The velocity of the body after the first rebound is
\(\begin{aligned}
& u=0.4 \times 20 \\
& u=8 \mathrm{~m} / \mathrm{s}
\end{aligned}\)
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
- Focal length of objective of an astronomical telescope is 1.5 m . Under normal adjustment, length of telescope is 1.56 m . Focal length of the eyepiece isMHT CET 2024 Easy
- The magnifying power of a refracting type of astronomical telescope is ' \(\mathrm{m}\) '. If focal length of eyepiece is doubled then the magnifying power will becomeMHT CET 2021 Easy
- Two concentric circular coils \(\mathrm{A}\) and \(\mathrm{B}\) have radii \(20 \mathrm{~cm}\) and \(10 \mathrm{~cm}\) respectively lie in the same plane. The current in coil A is \(0.5 \mathrm{~A}\) in anticlockwise direction. The current in coil B so that net field at the common centre is zero, isMHT CET 2023 Easy
- The voltage between the plates of a parallel plate capacitor of capacity \(1 \mu \mathrm{~F}\) is changing at the rate of \(4 \mathrm{~V} / \mathrm{s}\). the displacement current in the capacitor isMHT CET 2025 Medium
- A closed organ pipe and an open organ pipe have their first overtones identical in
frequency. Their lengths are in the ratioMHT CET 2020 Easy - A sound source is moving towards a stationary observer with \(\left(\frac{1}{10}\right)^{\text {th }}\) the speed of sound, The ratio of apparent to real frequency isMHT CET 2025 Medium
More PYQs from MHT CET
- What is the bond angle inMHT CET 2019 Easy
- Two coherent sources \(P\) and \(Q\) produce interference at point \(A\) on the screen where there is a dark band which is formed between \(4^{\text {th }}\) bright band and \(5^{\text {th }}\) bright band. Wavelength of light used is \(6000\)Å. The difference between \(P A\) and \(Q A\) isMHT CET 2016 Medium
- Oxygen dissociation curve shifts towards left due to increase in ____________ during internal respiration.MHT CET 2021 Hard
- A magnetizing field of \(100 \mathrm{~A} / \mathrm{m}\) produces a magnetic flux of \(2.4 \times 10^{-5} \mathrm{~Wb}\) in an iron bar of cross-sectional area \(0.3 \mathrm{~cm}^2\). The magnetic permeability of the iron bar in the SI unit isMHT CET 2022 Medium
- Identify the final product obtained when a mixture of vapours of phenol and hydrogen is passed over nickel catalyst at 433 K .MHT CET 2025 Medium
- What reagent is used in Etard reaction?MHT CET 2016 Easy