Rotational-Motion-Quiz-7

Rotational Motion Quiz-7

Dear Readers,

As per analysis for previous years, it has been observed that students preparing for NEET find Physics out of all the sections to be complex to handle and the majority of them are not able to comprehend the reason behind it. This problem arises especially because these aspirants appearing for the examination are more inclined to have a keen interest in Biology due to their medical background. 

Furthermore, sections such as Physics are dominantly based on theories, laws, numerical in comparison to a section of Biology which is more of fact-based, life sciences, and includes substantial explanations. By using the table given below, you easily and directly access to the topics and respective links of MCQs. Moreover, to make learning smooth and efficient, all the questions come with their supportive solutions to make utilization of time even more productive. Students will be covered for all their studies as the topics are available from basics to even the most advanced. 

Q1. A uniform rod of mass m and length l is suspended by means of two light inextensible strings as shown in figure. Tension in one string immediately after the other string is cut is

•  mg/2
•  mg
•  2mg
•  mg/4

Solution

Q2.An example of inelastic collision is

•  Scattering of α-particle from a nucleus
•  Collision of ideal gas molecules
•  Collision of two steel balls lying on a frictionless table
•  Collision of a bullet with a wooden block

Solution
(D)

Q3.  Look at the drawing given in the figure, which has been drawn with ink of uniform line-thickness. The mass of ink used to draw each of the two inner circles, and each of the two line segments is m. The mass of ink used to draw the outer circle is 6m. The coordinates of the centres of the different parts are : outer circle (0, 0) left inner circle (-a,a), right inner circle (a,a) vertical line (0, 0) and horizontal line (0, -a). The y- coordinate of the centre of mass of the ink in the drawing is

                                                  

•  a/10
•  a/8
•  a/12
•  a/3

Solution

Q4. A disc is rotating with an angular speed of ω. If a child sits on it, which of the following is conserved

•  Kinetic energy
•  Potential energy
•  Linear momentum
•  Angular Momentum

Solution
(D)

Q5.A metre stick is held vertically with one end on the floor and is then allowed to fall. If the end touching the floor is not allowed to slip, the other end will hit the ground with a velocity of

•  3.2 m/s
•  5.4 m/s
•  7.6 m/s
•  9.2 m/s

Solution
 

Q6. The instantaneous angular-position of a point on a rotating wheel is given by the equation θ(t)=2t³-6t². The torque on the wheel becomes zero at

•  t=2s
•  t=1s
• t=0.2s
•  t=0.25s

Solution

Q7.In the HCl molecule, the separation between the nuclei of the two atoms is about 1.27 Å (1 Å=10^-10 m). The approximate location of the centre of mass of the molecule, assuming the chlorine atom to be about 35.5 times massive as hydrogen is

•  1 Å
•  2.5 Å
•  1.24 Å
•  1.5 Å

Solution

Q8.A ball rolls without slipping. The radius of gyration of the ball about an axis passing through its centre of mass is K. If radius of the ball be R, then the fraction of total energy associated with its rotational energy will be

•  K²/R²
•  K²/K²+R²
•  R²/K²+R²
•  K²+R²/R²

Solution

Q9.A set of n identical cubical blocks lies at rest parallel to each other along a line on a smooth horizontal surface. The separation between the near surfaces of any two adjacent blocks is L. The block at one end is given a speed v towards the next one at time t=0. All collision are completely elastic. Then

•  The last block starts moving at time t=(n-1) L/v
•  The last block starts moving at time t=(n-1)L/2v
•  The centre of mass of the system will have a final speed v
•  The centre of mass of the system will have a final speed v/n

Solution

Q10. What constant force, tangential to the equator should be applied to the earth to stop its rotation in one day

•  1.3×10²²N
•  8.26×10²⁸ N
•  1.3×10²³ N
• None of these

Solution