JEE Mains · Physics · STD 11 - 5. work,energy,power and collision
A body is dropped on ground from a height \(h_1\) and after hitting the ground, it rebounds to a height \(h _2\) If the ratio of velocities of the body just before and after hitting ground is \(4\), then percentage loss in kinetic energy of the body is \(\frac{x}{4}\). The value of \(x\) is \(.......\)
- A \(374\)
- B \(373\)
- C \(375\)
- D \(365\)
Answer & Solution
Correct Answer
(C) \(375\)
Step-by-step Solution
Detailed explanation
Let \(V_1\) and \(V_2\) are velocity just before and just after hitting the floor. \(\frac{V_1}{V_2}=4 \Rightarrow V_1=4 V_2\) \(K E_{\text {bygove }}=\frac{1}{2} m V_1^2\) \(K E_{\text {affor }}=\frac{1}{2} m V_2^2=\frac{1}{2} \frac{m \cdot V_1^2}{16}\)…
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
- An elliptical loop having resistance \(R\), of semi major axis \(a,\) and semi inor axis \(b\) is placed in a magnetic field as shown in the figure. If the loop is rotated about the \(x-\) axis with angular frequency \(\omega\), the average power loss in the loop due to Joule heating is :
JEE Mains 2020 Hard - A cell \(E _{1}\) of \(emf 6 V\) and internal resistance \(2 \Omega\) is connected with another cell \(E _{2}\) of \(emf 4 V\) and internal resistance \(8 \Omega\) (as shown in the figure). The potential difference across points \(X\) and \(Y\) is............ \(V\)
JEE Mains 2021 Hard - A body is moving unidirectionally under the influence of a constant Power source. Its displacement in time \(t\) is proportional to _______.JEE Mains 2024 Hard
-
Choose the correct answer from the options given below.List\(-I\) List\(-II\) \(UV\) rays \((i)\) Diagnostic tool in medicine \(X-\) rays \((ii)\) Water purification Microwave \((iii)\) Communication, Radar Infrared wave \((iv)\) Improving visibility in foggy days JEE Mains 2022 Medium - The resistance \(R =\frac{ V }{ I },\) where \(V =(50 \pm 2) \;V\) and \(I=(20 \pm 0.2)\;A.\) The percentage error in \(R\) is \(x\%\). The value of \(x\) to the nearest integer is .........JEE Mains 2021 Medium
- A moving coil galvanometer has a coil with \(175\, turns\) and area \(1\, cm^2\) It uses a torsion band of torsion constant \(10^{-6}\, N\, -m/rad\). The coil is placed in a magnetic field \(B\) parallel to its plane. The coil deflects by \(10\) for a current of \(1\, mA\). The value of \(B\) (in Tesla) is approximatelyJEE Mains 2019 Medium
More PYQs from JEE Mains
- Let \(\left| {{{\vec A}_1}} \right| = 3,\,\left| {\vec A_2} \right| = 5\), and \(\left| {{{\vec A}_1} + {{\vec A}_2}} \right| = 5\). The value of \(\left( {2{{\vec A}_1} + 3{{\vec A}_2}} \right)\cdot \left( {3{{\vec A}_1} - 2{{\vec A}_2}} \right)\) isJEE Mains 2019 Hard
- If \(A\) and \(B\) are any two events such that \(P\left( A \right)\, = \frac{2}{5}\) and \(P\left( {A \cap \,B} \right)\, = \frac{3}{{20}},\) then the conditional probability, \(P\left( {A\,|\,A'\, \cup \,B')} \right),\) where \(A'\) denotes the complement of \(A,\) is equal toJEE Mains 2016 Hard
- The deflection in moving coil galvanometer falls from \(25\) divisions to \(5\) division when a shunt of \(24\ \Omega\) is applied. The resistance of galvanometer coil will be :JEE Mains 2024 Hard
- If the area of the region \(\left\{( x , y ): x ^{\frac{2}{3}}+ y ^{\frac{2}{3}} \leq 1 x + y \geq 0, y \geq 0\right\}\) is \(A\), then \(\frac{256 A }{\pi}\)JEE Mains 2022 Hard
- If \(y(\theta)=\frac{2 \cos \theta+\cos 2 \theta}{\cos 3 \theta+4 \cos 2 \theta+5 \cos \theta+2}\) then at \(\theta=\frac{\pi}{2}, y^{\prime \prime}+y^{\prime}+y\) is equal to :JEE Mains 2024 Hard
- A thin uniform rod \(( X )\) of mass M and length L is pivoted at a height \(\left(\frac{ L }{3}\right)\) as shown in the figure. The rod is allowed to fall from a vertical position and lie horizontally on the table. The angular velocity of this rod when it hits the table top, is _________ . (g = gravitational acceleration)
JEE Mains 2026 Hard