OnlineCBT
Physics · SYSTEMS OF PARTICLES AND ROTATIONAL MOTION
Practice questions & answers
Find a question, read its answer and explanation, then practise related questions.
Physics · Clear filters
1621 questions
Physics · PYQ NEET UG 2016(2)
A rectangular film of liquid is extended from \( (4\text{ cm} \times 2\text{ cm}) \) to \( (5\text{ cm} \times 4\text{ cm}) \). If the work done is \( 3 \times 10^{-4}\text{ J} \), the value of the surface tension of the liquid is
Read answer →Physics · SYSTEMS OF PARTICLES AND ROTATIONAL MOTION
Given two vectors \( \mathbf{a} = 3\hat{i} - 4\hat{j} + 5\hat{k} \) and \( \mathbf{b} = -2\hat{i} + \hat{j} - 3\hat{k} \), the cross product \( \mathbf{a} \times \mathbf{b} \) is equal to:
Read answer →Physics · WORK, ENERGY AND POWER
Three identical ball bearings 1, 2, and 3 are arranged on a frictionless horizontal table as shown. Ball 1 approaches balls 2 and 3 (initially at rest in contact) with velocity \( V \). If the collision is elastic, which of the following outcomes shown in Fig. 5.14 is physically possible?
Read answer →Physics · WORK, ENERGY AND POWER
A woman pushes a crate on a rough floor. For the first \( 12\text{ m} \), she applies a constant force of \( 120\text{ N} \). Over the next \( 8\text{ m} \), her applied force decreases linearly to \( 40\text{ N} \). Throughout the motion, an opposing frictional force of \( 60\text{ N} \) acts on the crate. The net work done on the crate during the entire \( 20\text{ m} \) displacement is:
Read answer →Physics · PYQ NEET UG 2019(2)
The reading of an ideal voltmeter in the circuit shown is,
Read answer →Physics · WORK, ENERGY AND POWER
A bob of mass \( m \) is attached to a light string of length \( L \) and oscillates in a vertical circle. If the horizontal velocity imparted at the lowest point \( A \) is just sufficient for the string to become slack at the topmost point \( C \), the ratio of the tension in the string at the lowest point \( A \) to that at the horizontal position \( B \) is:
Read answer →Physics · SYSTEMS OF PARTICLES AND ROTATIONAL MOTION
Consider the following statements regarding rotational motion about a fixed axis: (A) Only those components of external torques that lie along the axis of rotation can cause the body to rotate about the axis. (B) Torques perpendicular to the fixed axis are balanced by the constraint forces exerted by the hinges/supports. (C) Forces parallel to the axis of rotation produce non-zero torque about that axis. (D) The rate of work done by an external torque \( \tau \) rotating a body with angular speed \( \omega \) is given by \( P = \tau \omega \). How many of the above statements are correct?
Read answer →Physics · PYQ NEET UG 2019(2)
A person travelling in a straight line moves with a constant velocity \( v_1 \) for certain distance 'x' and with a constant velocity \( v_2 \) for next equal distance. The average velocity v is given by the relation
Read answer →Physics · LAWS OF MOTION
A banked circular track is designed such that \( \tan\theta = \frac{1}{3} \). The coefficient of static friction between tyres and the track is \( \mu_s = \frac{1}{3} \). What is the percentage increase in the maximum permissible speed \( v_{\max} \) over the optimum speed \( v_0 \) (where friction is zero)?
Read answer →Physics · Electrostatic Potential
A capacitor of capacitance \( C_1 = 4\, \mu\text{F} \) is charged to \( 50\text{ V} \) and another capacitor \( C_2 = 6\, \mu\text{F} \) is charged to \( 100\text{ V} \). If they are connected together in parallel with plates of like polarity connected together, the final common potential difference across the combination is:
Read answer →Physics · PYQ NEET UG 2025
An electric dipole with dipole moment \( 5 \times 10^{-6}\text{ Cm} \) is aligned with the direction of a uniform electric field of magnitude \( 4 \times 10^5\text{ N/C} \). The dipole is then rotated through an angle of \( 60^\circ \) with respect to the electric field. The change in the potential energy of the dipole is :
Read answer →Physics · SYSTEMS OF PARTICLES AND ROTATIONAL MOTION
In an L-shaped uniform lamina formed by three identical squares of side length \( b = 2\text{ m} \) as oriented in Fig. 6.11 (with bottom-left square at origin having vertices from \( (0,0) \) to \( (2,2) \)), the coordinate of the centre of mass is:
Read answer →Physics · MOTION IN A STRAIGHT LINE
A particle moves along a straight line such that its position \( x \) at time \( t \) is given by \( x = t^3 - 6t^2 + 9t + 5 \). At what time(s) is the velocity of the particle zero?
Read answer →Physics · MOTION IN A PLANE
The resultant of two vectors \( \mathbf{P} \) and \( \mathbf{Q} \) is perpendicular to \( \mathbf{P} \). If the magnitude of the resultant is equal to half of the magnitude of \( \mathbf{Q} \), then the angle between \( \mathbf{P} \) and \( \mathbf{Q} \) is:
Read answer →Physics · SYSTEMS OF PARTICLES AND ROTATIONAL MOTION
A particle moves with uniform speed \( v \) along a circle of radius \( R \) centered at the origin in the \( xy \)-plane. The angular momentum of the particle about a point \( P(2R, 0) \) on the \( x \)-axis varies between minimum and maximum values \( L_{\min} \) and \( L_{\max} \). The ratio \( \frac{L_{\max}}{L_{\min}} \) is:
Read answer →Physics · SYSTEMS OF PARTICLES AND ROTATIONAL MOTION
Consider a system of \( n \) particles where the position vector of each particle relative to the centre of mass is \( \mathbf{r}'_i \). The value of the vector sum \( \sum_{i=1}^n m_i \mathbf{r}'_i \) is always:
Read answer →Physics · PYQ NEET UG 2019(1)
The total energy of an electron in an atom in an orbit is \( -3.4\text{ eV} \). Its kinetic and potential energies are, respectively
Read answer →Physics · UNITS AND MEASUREMENT
According to the NCERT rounding-off rules, the numbers \( 3.745 \) and \( 3.735 \), when rounded off to three significant figures, become respectively:
Read answer →Physics · MOTION IN A STRAIGHT LINE
Match List-I with List-II for motion under gravity (ball thrown vertically upward with initial speed \( v_0 \)): List-I List-II A Time taken to reach peak height I \( v_0 \) B Maximum height reached above launch point II \( \frac{2 v_0}{g} \) C Total time of flight to return to launch level III \( \frac{v_0}{g} \) D Speed upon returning to launch level IV \( \frac{v_0^2}{2g} \) Choose the correct answer from the options given below:
Read answer →Physics · SYSTEMS OF PARTICLES AND ROTATIONAL MOTION
An engine needs to transmit a torque of \( 180 \text{ N m} \) to maintain a rotor at a uniform angular speed of \( 200 \text{ rad s}^{-1} \). If the engine operates with an efficiency of \( 75\% \), the power input supplied to the engine is:
Read answer →Physics · MOTION IN A STRAIGHT LINE
Match List-I with List-II regarding graph features in one-dimensional motion: List-I List-II A Position-time curve concave upwards (\( d^2x/dt^2 > 0 \)) I Net displacement over time interval B Position-time curve concave downwards (\( d^2x/dt^2 < 0 \)) II Motion with negative acceleration turning back after stopping C v-t graph with negative slope crossing time axis III Motion with positive acceleration (\( a > 0 \)) D Area under v-t graph between \( t_1 \) and \( t_2 \) IV Motion with negative acceleration (\( a < 0 \)) Choose the correct answer from the options given below:
Read answer →Physics · PYQ NEET UG 2021
An infinitely long straight conductor carries a current of \( 5\text{ A} \) as shown. An electron is moving with a speed of \( 10^5\text{ m/s} \) parallel to the conductor. The perpendicular distance between the electron and the conductor is \( 20\text{ cm} \) at an instant. Calculate the magnitude of the force experienced by the electron at that instant.
Read answer →Physics · PYQ NEET UG 2019(2)
