JEE Mains · Physics · STD 11 - 5. work,energy,power and collision
A car accelerates from rest to \(u\,m / s\). The energy spent in this process is \(E\,J\). The energy required to accelerate the car from \(u\,m / s\) to \(2u\,m / s\) is \(nE\,J\). The value of \(n\) is ..............
- A \(6\)
- B \(3\)
- C \(9\)
- D \(12\)
Answer & Solution
Correct Answer
(B) \(3\)
Step-by-step Solution
Detailed explanation
\(E _1=\frac{1}{2} m u^2-0=\frac{1}{2} mu ^2= E\) \(E _2=\frac{1}{2} m (2 u )^2-\frac{1}{2} m u^2=\frac{3}{2} m u^2=3 E\)
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 wire of uniform resistance \(\lambda \Omega / m\) is bent into a circle of radius \(r\) and another piece of wire with length 2 r is connected between points A and B \(( AOB )\) as shown in figure. The equivalent resistance between points A and B is ___________\(\Omega\).
JEE Mains 2026 Easy - As shown in the figure, in Young's double slit experiment, a thin plate of thickness \(t =10\,\mu m\) and refractive index \(\mu _{1}=1.2\) is inserted infront of slit \(S _1\). The experiment is conducted in air \((\mu=1)\) and uses a monochromatic light of wavelength \(\lambda=500\,nm\). Due to the insertion of the plate, central maxima is shifted by a distance of \(x \beta_0 . \beta_0\) is the fringe-width before the insertion of the plate.The value of the \(x\) is \(.............\)
JEE Mains 2023 Medium - The position of a particle as a function of time \(t\), is given by \(x\left( t \right) = at+ b{t^2} - c{t^3}\) where \(a, b\) and \(c\) are constants. When the particle attains zero acceleration, then its velocity will beJEE Mains 2019 Hard
- Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R
Assertion A: In electrostatics, a conductor does not store any net charge inside.
Reason R: Inside the capacitor (with no dielectric medium), the free charge carriers, if placed between the plates of capacitor, experience force and drift.
Choose the correct answer from the options given belowJEE Mains 2026 Medium - When a metal surface is illuminated by light of wavelength \(\lambda\), the stopping potential is \(8 \mathrm{~V}\). When the same surface is illuminated by light of wavelength \(3 \lambda\), stopping potential is \(2 \mathrm{~V}\). The threshold wavelength for this surface is _______.JEE Mains 2024 Hard
- A brass wire of length 2 m and radius 1 mm at \(27^{\circ} C\) is held taut between two rigid supports. Initially it was cooled to a temperature of \(-43^{\circ} C\) creating a tension T in the wire. The temperature to which the wire has to be cooled in order to increase the tension in it to 1.4 T , is _________ \({ }^{\circ} C\)JEE Mains 2026 Easy
More PYQs from JEE Mains
- If the system of equations \(2 x+y-z=5\) \(2 x-5 y+\lambda z=\mu\) \(x+2 y-5 z=7\) has infinitely many solutions, then \((\lambda+\mu)^2+(\lambda-\mu)^2\) is equal toJEE Mains 2023 Hard
- A constant Power delivering machine has towed a box, which was initially at rest, along a horizontal straight line. The distance moved by the box in time \('t'\) is proportional toJEE Mains 2021 Hard
- If the length of the perpendicular drawn from the point \(P ( a , 4,2), a >0\) on the line \(\frac{x+1}{2}=\frac{y-3}{3}=\frac{z-1}{-1}\) is \(2 \sqrt{6}\) units and \(Q \left(\alpha_{1}, \alpha_{2}, \alpha_{3}\right)\) is the image of the point \(P\) in this line, then \(a+\sum_{i=1}^{3} \alpha_{i}\) is equal to.JEE Mains 2022 Hard
- Let S be the set of all the words that can be formed by arranging all the letters of the word GARDEN. From the set S, one word is selected at random. The probability that the selected word will NOT have vowels in alphabetical order is :JEE Mains 2025 Medium
- In the expansion of \((1+x)\left(1-x^2\right)\left(1+\frac{3}{x}+\frac{3}{x^2}+\frac{1}{x^3}\right)^5, x \neq 0\), the sum of the coefficient of \(x^3\) and \(x^{-13}\) is equal toJEE Mains 2024 Hard
- A metallic rod of length ' \(L\) ' is rotated with an angular speed of ' \(\omega\) ' normal to a uniform magnetic field ' \(B\) ' about an axis passing through one end of rod as shown in figure. The induced emf will be :
JEE Mains 2023 Medium