JEE Mains · Physics · STD 11 - Work,energy,power and collision
- JEE Mains 2019
- Medium
- MCQ
A bullet of mass \(20\,g\) has an initial speed of \(1\,ms^{-1}\) just before it starts penetrating a mud wall of thickness \(20\,cm.\) If the wall offers a mean resistances of \(2.5 \times 10^{-2}\,N,\) the speed of the bullet after emerging from the other side of the wall is close to .............. \(\mathrm{ms}^{-1}\)
Pick an option to check your answer.
Answer & Solution
Correct Answer
(A) \(0.7\)
Step-by-step Solution
Detailed explanation
\(\begin{array}{l}
2.5 \times {10^{ - 2}} \times 0.2 = \frac{1}{2} \times 20 \times {10^{ - 3}}\left\{ { - {V^2} + {1^2}} \right\}\\
5 \times {10^{ - 3}} = 10 \times {10^{ - 3}}\left( {1 - {V^2}} \right)\\
1 - {V^2} = \frac{1}{2}\,\,;\,\,{V^2} = \frac{1}{2}\,\,;\,\,V = \frac{1}{{\sqrt 2 }}\, = 0.7
\end{array}\)
2.5 \times {10^{ - 2}} \times 0.2 = \frac{1}{2} \times 20 \times {10^{ - 3}}\left\{ { - {V^2} + {1^2}} \right\}\\
5 \times {10^{ - 3}} = 10 \times {10^{ - 3}}\left( {1 - {V^2}} \right)\\
1 - {V^2} = \frac{1}{2}\,\,;\,\,{V^2} = \frac{1}{2}\,\,;\,\,V = \frac{1}{{\sqrt 2 }}\, = 0.7
\end{array}\)
More questions from Physics
- Choose the correct nuclear process from the below options.
[p: proton, n : neutron, \(\mathrm{e}^{-}\): electron, \(\mathrm{e}^{+}\): positron, \(v:\) neutrino, \(\bar{v}\) : antineutrino]JEE Mains 2025 Easy - If electronic charge \(e\), electron mass \(m\), speed of light in vacuum \(c\) and Planck 's constant \(h\) are taken as fundamental quantities, the permeability of vacuum \(\mu _0\) can be expressed in units ofJEE Mains 2015 Hard
- Particle \(A\) of mass \(m _{1}\) moving with velocity \((\sqrt{3} \hat{i}+\hat{j})\, ms ^{-1}\) collides with another particle \(B\) of mass \(m _{2}\) which is at rest initially. Let \(\overrightarrow{ V }_{1}\) and \(\overrightarrow{ V }_{2}\) be the velocities of particles \(A\) and \(B\) after collision respectively. If \(m _{1}=2\, m _{2}\) and after collision \(\overrightarrow{ V }_{1}=(\hat{ i }+\sqrt{3} \hat{ j })\, ms ^{-1},\) the angle between \(\overrightarrow{ V }_{1}\) and \(\overrightarrow{ V }_{2}\) is\(......^o\)JEE Mains 2020 Hard
- A negative test charge is moving near a long straight wire carrying a current. The force acting on the test charge is parallel to the direction of the current. The motion of the charge isJEE Mains 2017 Medium
- A magnet hung at \(45^{\circ}\) with magnetic meridian makes an angle of \(60^{\circ}\) with the horizontal. The actual value of the angle of dip is.JEE Mains 2022 Medium
- A liquid of density \(\rho \) is coming out of a hose pipe of radius \(a\) with horizontal speed \(v\) and hits a mesh. \(50\%\) of the liquid passes through the mesh unaffected. \(25\%\) looses all of its momentum and \(25\%\) comes back with the same speed. The resultant pressure on the mesh will beJEE Mains 2019 Hard
More PYQs from JEE Mains
- A charge of \(4.0 \mu \mathrm{C}\) is moving with a velocity of \(4.0 \times 10^6 \mathrm{~ms}^{-1}\) along the positive \(\mathrm{y}\)-axis under a magnetic field \(\vec{B}\) of strength \((2 \hat{k})\ T\). The force acting on the charge is \(x \hat{i} N\). The value of \(x\) is _______.JEE Mains 2024 Hard
- Two radioactive substances A and B of mass numbers \(200\) and \(212\) respectively, shows spontaneous \(\alpha\)-decay with same \(Q\) value of \(1\) MeV. The ratio of energies of \(\alpha\)-rays produced by A and B is ________.JEE Mains 2026 Medium
- In a physical balance working on the principle of moments, when \(5\, mg\) weight is placed on the left pan, the beam becomes horizontal. Both the empty pans of the balance are of equal mass. Which of the following statements is correct?JEE Mains 2017 Medium
- This question has Statement \(- 1\) and Statement \(-2\). Of the four choices given after the Statements, choose the one that best describes the two Statements.
Statement \(1\) : The internal energy of a perfect gas is entirely kinetic and depends only on absolute temperature of the gas and not on its pressure or volume.
Statement \(2\) : A perfect gas is heated keeping pressure constant and later at constant volume. For the same amount of heat the temperature of the gas at constant pressure is lower than that at constant volume.JEE Mains 2013 Medium - The work function of a substance is \(3.0\ \mathrm{eV}\). The longest wavelength of light that can cause the emission of photoelectrons from this substance is approximately _______.JEE Mains 2024 Hard
- A body of mass \(m= 10^{-2}\) \(kg\) is moving in a medium and experiences a frictional force \(F= -kv^2\). Its initial speed is \(v_0= 10\) \(ms^{-1}\). If, after \(10\; s\), its energy is \(\frac{1}{8}\) \(mv_0^2\) the value of \(k\) will beJEE Mains 2017 Hard