Recent questions tagged medium

If $\overrightarrow b\:\:is\:\: \perp\:\:to \:\:\overrightarrow a+\overrightarrow b\:\:and\:\:\overrightarrow a\:\:is\:\:\perp \:\:to\:\:2\overrightarrow b+\overrightarrow a$ then $|\overrightarrow a|=?$

asked Dec 8, 2013 by rvidyagovindarajan_1

1 answer

A constant external torque acts for a very brief $\Delta t$ on a rotating system having moment of inertia I.

asked Dec 8, 2013 by meena.p

0 answers

Two horizontal discs of different radius are free to rotate about their central vertical axes. One is given some angular velocity, the other is stationary . Their rims are now brought in contact. There is friction between the rims.

asked Dec 8, 2013 by meena.p

0 answers

If $\overrightarrow v=2\hat i+\hat j-\hat k, \:\:and\:\:\overrightarrow w=\hat i+3\hat k\:\:and\:\:\overrightarrow u$ is a unit vector, then the maximum value of $[\overrightarrow u\:\overrightarrow v\:\overrightarrow w]=?$

asked Dec 8, 2013 by rvidyagovindarajan_1

1 answer

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?

asked Dec 8, 2013 by meena.p

1 answer

A man standing on a platform holds weight in his out stretched arms. The system rotates freely about a central vertical axis. If he now draws the weights inwards close to his body. 1) the angular velocity of the system will decrease 2) the angular momentum of the system will decrease. 3) the kinetic energy of the system will increase 4) he will have to expend some energy to draw the weights in Which of the following is correct?

asked Dec 8, 2013 by meena.p

0 answers

A body is in equilibrium under the influence of a number of a forces. Each force has a different line of action. The minimum number of forces required is

asked Dec 8, 2013 by meena.p

0 answers

When slightly different weights are placed on the two pane of a beam balance, the beam comes to rest at an angle with the horizontal. The beam is supported at a single point P by a pivot.

asked Dec 8, 2013 by meena.p

0 answers

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?

asked Dec 8, 2013 by meena.p

1 answer

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?

asked Dec 8, 2013 by meena.p

1 answer

If $|\overrightarrow a|=|\overrightarrow c|=1, \:|\overrightarrow b|=4,\:\overrightarrow a\times\overrightarrow b=2\overrightarrow a\times\overrightarrow c\:and\:$ if the angle between $\overrightarrow b\:and\:\:\overrightarrow c$ is $cos^{-1}\large\frac{1}{4}$ then $\overrightarrow b-2\overrightarrow c=?$

asked Dec 7, 2013 by rvidyagovindarajan_1

1 answer

If $\overrightarrow a$ is any vector such that $\overrightarrow a\times \hat i+2\overrightarrow a-5\hat k=\overrightarrow 0$, then $\overrightarrow a=?$

asked Dec 6, 2013 by rvidyagovindarajan_1

1 answer

For toppling of the regular hexagon shown. the coefficient of friction must be

asked Dec 6, 2013 by meena.p

1 answer

The bond energy (in kcal/mol) of C-C single bond is approximately

asked Dec 6, 2013 by sreemathi.v

1 answer

Which of the following species has bond order different from that in CO?

asked Dec 6, 2013 by sreemathi.v

1 answer

A uniform cube of side 'a' and mass 'm' rests on a rough horizontal table. A horizontal force 'F' is applied normal to one of the faces at a point that is directly above at a height $\large\frac{3a}{4}$ above the base. The minimum value of 'F' for which the cube begins to lilt about the edge is (assume cube does not slide)

asked Dec 6, 2013 by meena.p

1 answer

Which of the following is a false statement?

asked Dec 6, 2013 by sreemathi.v

1 answer

Which of the following represent the correct order of increase in covalent character?

asked Dec 6, 2013 by sreemathi.v

1 answer

Which of the following represent the correct order of decrease in covalent character?

asked Dec 6, 2013 by sreemathi.v

1 answer

Which of the following represent the correct order of increase in covalent character?

asked Dec 6, 2013 by sreemathi.v

1 answer

Which of the following represent the correct order of decreasing lattice energy?

asked Dec 6, 2013 by sreemathi.v

1 answer

Which of the following compounds does not obey the octet rule?

asked Dec 6, 2013 by sreemathi.v

2 answers

Which of the following does not obey the octet rule?

asked Dec 6, 2013 by sreemathi.v

1 answer

Which of the following obeys the octet rule?

asked Dec 6, 2013 by sreemathi.v

1 answer

If $\overrightarrow a,\:\overrightarrow b,\:\overrightarrow c$ are any three unit vectors such that $\overrightarrow a.\overrightarrow b=\overrightarrow a.\overrightarrow c=0$ and the angle between $\overrightarrow b\:\:and\:\:\overrightarrow c $ is $\large\frac{\pi}{6}$, then $\overrightarrow b\times\overrightarrow c=?$

asked Dec 5, 2013 by rvidyagovindarajan_1

1 answer

If $\overrightarrow a,\:\overrightarrow b,\:\overrightarrow c$ are any three vectors such that $\overrightarrow a\times\overrightarrow b=\overrightarrow c\:\:and\:\:\overrightarrow b\times\overrightarrow c=\overrightarrow a$, then the magnitude of $\overrightarrow b$ is?

asked Dec 5, 2013 by rvidyagovindarajan_1

1 answer

Identify the product

asked Dec 4, 2013 by sreemathi.v

1 answer

If $D\:\:and\:\:E$ are mid points of the side $\overline {AB}\:\:and\:\:\overline {AC}$ of a $\Delta \:ABC$, then $\overrightarrow {BE}+\overrightarrow {DC}=?$

asked Dec 3, 2013 by rvidyagovindarajan_1

1 answer