MHT CET · Physics · Work Power Energy
A block of mass 'm', kept on a horizontal surface, is moved through a distance 's'
by applying a horizontal force (F) to it. What is the work done by the normal
reaction?
- A \(\frac{\mathrm{F}}{\mathrm{s}}\)
- B \(\mathrm{Fs}\)
- C zero
- D \(\frac{\mathrm{S}}{\mathrm{F}}\)
Answer & Solution
Correct Answer
(C) zero
Step-by-step Solution
Detailed explanation
In the first case, the centre of gravity is at a height \(=\frac{b}{2}\) \(\therefore\) Work done \(=\mathrm{mgh}=\mathrm{mg}\left(\frac{b}{2}\right)\)
In the second case, the height of the centre of gravity \(=\frac{L}{2}\)
\(\therefore\) Work done \(=m g \frac{L}{2} \therefore L>b\)
\(\therefore\) Extra work done \(\quad=m g\left(\frac{L-b}{2}\right)\)
In the second case, the height of the centre of gravity \(=\frac{L}{2}\)
\(\therefore\) Work done \(=m g \frac{L}{2} \therefore L>b\)
\(\therefore\) Extra work done \(\quad=m g\left(\frac{L-b}{2}\right)\)
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
- The mass and radius of the earth and moon are \(M, R\) and \(m, r\) respectively. The distance between their centers is \(d\). The minimum velocity with which a particle of mass \(m_0\) should be projected from the midpoint between them so that it could reach infinity isMHT CET 2022 Hard
- When two tuning forks are sounded together, 5 beats per second are heard. One of the forks is in unison with \(0.97 \mathrm{~m}\) length of sonometer wire and the other is in unison with \(0.96 \mathrm{~m}\) length of the same wire. The frequencies of the two tuning forks areMHT CET 2023 Medium
- The primary and secondary voltage of an ideal step-down transformer is \(200 \mathrm{~V}\) and \(25 \mathrm{~V}\) respectively. The secondary is connected to a device, which draws a current of \(2 \mathrm{~A}\). The current in the primary isMHT CET 2022 Easy
- Two bar magnets \(A\) and \(B\) are geometrically similar but the magnetic moment of \(A\) is twice that of \(B\). \(T_1\) is the time period of oscillation when their like poles are kept together. When unlike poles are kept together, the time period of oscillation is \(\mathrm{T}_2\). The ratio \(\mathrm{T}_1: \mathrm{T}_2\) will beMHT CET 2025 Medium
- The coil of inductance \(0.25 \mathrm{mH}\) has a reactance of \(330 \Omega\), when connected to an a.c. source. The frequency of a.c. source is (Take \(\left.\pi=\frac{22}{7}\right)\)MHT CET 2022 Easy
- The waves which are reflected back to the earth by ionos phere isMHT CET 2009 Medium
More PYQs from MHT CET
- Two wires of same material are vibrating under the same tension. If the first overtone of first wire is equal to the second overtone of second wire and radius of first wire is twice the radius of the second then the ratio of length of first wire to second wire isMHT CET 2020 Medium
- Which among the following reagents forms alcohol when reacted with \(\mathrm{R}-\mathrm{COOH}\) ?MHT CET 2022 Easy
- A glass slab has refractive index ' \(\mu\) ' with respect to air and the critical angle for a ray of light in going from glass to air is ' \(\theta\) ' If a ray of light is incident from air on the glass with angle of incidence ' \(\theta\) ', then the corresponding angle of refraction isMHT CET 2021 Medium
- Which among the following solutions has minimum boiling point elevation?MHT CET 2023 Easy
- A galvanometer has resistance ' \(\mathrm{G}\) ' and range ' \(\mathrm{V} g\) '. How much resistance is required to read voltage upto ' \(\mathrm{V}\) ' volt?MHT CET 2023 Medium
- Which plant hormone prevents pre-mature fruit drop in apple, pear and orange?MHT CET 2022 Medium