Recent questions and answers in Physics

The motion of a sphere moving on a rough horizontal surface change from pure sliding (without rolling) to pure rolling (with out slipping) . In this process, the force of friction. 1) initially acts opposite to the direction of motion and later in the direction of motion. 2) causes linear retardation 3) causes angular acceleration 4) stops acting when pure rolling begins. Which of the following is correct?

answered 1 day ago by blsaketh33

1 answer

A solid sphere of mass m is lying at rest on a rough horizontal surface. The coefficient of friction between the ground and sphere is $\mu$. The maximum value of F, so that the sphere will not slip is equal to

answered Apr 19 by jainnanu010

2 answers

A body covers a certain distance x in equal thirds - the first third of distance with speed v$_1$, the second third with a speed of v$_2$ and the last third with a speed of v$_3$. What is the average speed of the body over time?

answered Apr 16 by ushapattima

2 answers

A spherical body of radius R rolls on a horizontal surface with linear velocity $V$. Let $L_1$ and $L_2$ be the magnitude of angular momentum of the body about the centre of mass and point of contact P respectively. a) $L_2=L_1$ if radius of gyration $k=R$ b) $L_2=2L_1$ for all cases. c) $L_2 > 2L_1$ if radius of gyration $K < R$ d) $L_1> L_2$ if radius of gyration $ K > R$ Which of the following is correct?

answered Apr 9 by kingsumit011

1 answer

Hot air balloon is an application of what law?

answered Mar 30 by mahawarravi036

2 answers

Which of the following does not represent Boyle's law?

answered Mar 28 by mahawarravi036

3 answers

Three capacitors, each of capacitance C are connected to a battery of voltage V. When key K is closed, the charge which will flow through the battery is (see figure).

asked Mar 22 by guptakanishq1

0 answers

A ball is dropped from a height of h from ground. If the coefficient of restitution is e, the height to which the ball goes up after it rebounds for the nth time is

answered Mar 5 by yashuvats.42

2 answers

A man spinning in free space changes of his body e.g by spreading his arms and curling up. By doing this, he can change his 1) moment of inertia 2) angular momentum 3) angular velocity 4) rotational kinetic energy in this Which of the following is correct?

answered Feb 28 by priyanka.c

2 answers

The velocity of electromagnetic radiation in a medium of permittivity $ \in_0$ and permeability $ \mu_0$ is given by :

answered Jan 16 by jk6765001

2 answers

A person looks in to a spherical mirror . The size of image of his face is twice the actual size of his face. If the face is at distance 20 cm then find the radius of curvature of mirror.

answered Dec 1, 2017 by br.singh21914

2 answers

A horizontal disc rotates freely about a vertical axis through its centre. A ring, having the same mass and radius as the disc , is now gently placed on the disc. After some time, the two rotate with a common angular velocity. 1) some friction exits between the disc and the ring 2) the angular mometum of disc plus ring is conserved. 3) the final common angular velocity is $\large\frac{2}{3}$ rd of the initial angular velocity of disc. 4) $\large\frac{2}{3}$ rd of the initial kinetic energy is converted to heat. Which of the following is correct?

answered Oct 8, 2017 by vlalithambica

1 answer

From the top of a building 40 m tall, a ball a thrown vertically upwards with a velocity of $10\; ms^{-1}$ After how long will the ball hit the ground?

answered Aug 13, 2017 by sl0224422

2 answers

A person sitting in an open car moving at constant velocity throws a ball vertically up into air. The ball falls

answered Jul 13, 2017 by akashrao0005

2 answers

Minimum size of plane mirror, required to see full image of an observer is :

answered Jun 20, 2017 by parthgite94

2 answers

Find the dimension of physical quantity $X$ in the equation $Force=\large\frac{X}{Density}$

answered May 14, 2017 by muskaans095

2 answers

In the circuit as shown in the figure what is the potential difference between P and Q.

answered May 13, 2017 by nikunjjain285

1 answer

The trajectory of a projectile in a vertical plane is $y=ax-bx^2$ where $a$ and $b$ are constants. The maximum height attained by the particle and the angle of projection from horizontal are

answered Apr 24, 2017 by vipul.saini442

2 answers

Two identical particles , each having a charge of $\;2\times10^{-4}\;C\;$ and mass 10g are kept at a separation of 10 cm and released . What would be the speeds of the particles when the separation becomes large ?

answered Apr 19, 2017 by mahajanmridul1997

2 answers

electric charge Q,Q and -2Q resp. are placed at the three corners of an equilateral triangle of side a . magnitude of the elctrical dipole moment of the system is

answered Mar 23, 2017 by abdulsalamottathil

2 answers

a body is projected vertically upward from the earths surface such that it reaches a height equal to the radius of the earth above its surface.find the velocity of projection

answered Feb 3, 2017 by prekshu.02

1 answer

A 150m long train is moving with uniform velocity of 45km / h. The time taken by train to cross the bridge of length 850m is ?

answered Jan 29, 2017 by suchala2002

3 answers

Dhoni throws his bat vertically upwards with an initial velocity of $26.2\;m/s$ Determine the height to which the bat will rise above its initial height.

answered Aug 14, 2016 by donkadasnd

2 answers

Two identical charged spheres are suspended by strings of equal length . The strings make an angle of $\;60^{0}\;$ with each other . When suspended in a liquid of density $\;0.5 g/cc,\;$ the angle remains the same . The dielectric constant of the liquid is [density of material of sphere is $\;1.5 g/cc\;$]

answered Jun 24, 2016 by dongrearchit

2 answers

Two identical ladders are arranged as shown in the figure, resting on a horizontal surface. Mass of each ladder is M and length L. A block of mass m hangs from the apex point P. If the system is in equilibrium, find direction and magnitude of friction force acting at A or B.

answered Apr 1, 2016 by vijayalakshmi.r

1 answer

A particle of mass m is travelling with a constant velocity $\overrightarrow {V} =V_0 \hat i$ along the line $y=b,z=0$. Let $dA$ be the area swept out by the position vector from the origin to the particle in time at end L be the magnitude of angular momentum of particle about orgin at any time t. Then 1) L= constant 2) $\large\frac{dA}{dt}=\frac{L}{m}$ 3) $\large\frac{dA}{dt}= \frac{2L}{m}$ 4) $\large\frac{dA}{dt}=\frac{L}{2m}$ Which of the following is correct?

answered Apr 1, 2016 by vijayalakshmi.r

1 answer