JEE Mains · Physics · STD 11 - Motion in plane
- JEE Mains 2019
- Hard
- MCQ
A body is projected at \(t = 0\) with a velocity \(10\,ms^{-1}\) at an angle of \(60^o\) with the horizontal. The radius of curvature of its trajectory at \(t=1\,s\) is \(R.\) Neglecting air resistance and taking acceleration due to gravity \(g = 10\,ms^{-2},\) the radius of \(R\) is ........ \(m\)
Pick an option to check your answer.
Answer & Solution
Correct Answer
(B) \(2.8\)
Step-by-step Solution
Detailed explanation
\(\begin{array}{l}
at\,t = 1\\
\,{u_x} = 5,\,{u_y} = 5\sqrt 3 \\
{v_y} = 5\sqrt 3 - 10\,\,;\,\,\,{v_x} = 5\\
\tan \,\theta \, = - 2\left( {2 - \sqrt 3 } \right) \Rightarrow \theta = - {30^ \circ }\\
R = \frac{{{v^2}}}{{a \bot }} = \frac{{{{10}^2}}}{{\left( {10\,\cos \,{{30}^ \circ }} \right)}}
\end{array}\)
at\,t = 1\\
\,{u_x} = 5,\,{u_y} = 5\sqrt 3 \\
{v_y} = 5\sqrt 3 - 10\,\,;\,\,\,{v_x} = 5\\
\tan \,\theta \, = - 2\left( {2 - \sqrt 3 } \right) \Rightarrow \theta = - {30^ \circ }\\
R = \frac{{{v^2}}}{{a \bot }} = \frac{{{{10}^2}}}{{\left( {10\,\cos \,{{30}^ \circ }} \right)}}
\end{array}\)
\(\begin{array}{l}
\,\, = \frac{{10}}{{\sqrt 3 }} \times 2\, = \frac{{20}}{{\sqrt 3 }}m\\
\frac{{{5^2} + {{\left( {10 - 5\sqrt 3 } \right)}^2}}}{{10\,\cos \theta }} = \frac{{200 - 100\sqrt 3 }}{{10 \times 0.965}} = 2.8m
\end{array}\)
More questions from Physics
- If momentum \([ P ]\), area \([ A ]\) and time \([ T ]\) are taken as fundamental quantities, then the dimensional formula for coefficient of viscosity is :JEE Mains 2022 Medium
- A rectangular parallelopiped is measured as \(1\,cm \times 1\,cm \times 100\,cm\). If its specific resistance is \(3 \times 10^{-7}\,\Omega\,m\), then the resistance between its two opposite rectangular faces will be \(..........x^{-7} \Omega\).JEE Mains 2023 Easy
- Four resistances \(40 \ \Omega, 60\ \Omega, 90\ \Omega\) and \(110\ \Omega\) make the arms of a quadrilateral \(A,B,C,D\). Across \(AC\) is a battery of emf \(40\, V\) and internal resistance negligible. The potential difference across \(BD\) is \(V\) is......
JEE Mains 2020 Medium - A copper block of mass \(5.0\, kg\) is heated to a temperature of \(500^{\circ} C\) and is placed on a large ice block. What is the maximum amount of ice (ઇન \(kg\)) that can melt? [Specific heat of copper: \(0.39\, Jg ^{-1 \circ} C ^{-1}\) and latent heat of fusion of water : \(335 \,J g ^{-1}\) ]JEE Mains 2022 Medium
- A simple pendulum with length \(100\,cm\) and bob of mass \(250\,g\) is executing S.H.M. of amplitude \(10\,cm\). The maximum tension in the string is found to be \(\frac{x}{40}\,N\). The value of \(x\) is \(..........\).JEE Mains 2023 Hard
- If a copper wire is stretched to increase its length by \(20 \% \). The percentage increase in resistance of the wire is \(..........\%\)JEE Mains 2023 Medium
More PYQs from JEE Mains
- A \(12.5\,eV\) electron beam is used to bombard gaseous hydrogen at room temperature. The number of spectral lines emitted will be:JEE Mains 2023 Hard
- A parallel plate capacitor has plate of length \('l',\) width \('w'\) and separation of plates is \('d'.\) It is connected to a battery of emf \(V\). A dielectric slab of the same thickness '\(d\)' and of dielectric constant \(k =4\) is being inserted between the plates of the capacitor. At what length of the slab inside plates, will be energy stored in the capacitor be two times the initial energy stored\(?\)JEE Mains 2020 Hard