Tag: motion of system of particles and rigid bodies

Questions Related to motion of system of particles and rigid bodies

When the centre of gravity of a body lies at the point of suspension or support, the body is said to be in _____ equilibrium. Fill in the blank. 

rotational equilibrium option b: engineering physics motion of system of particles and rigid bodies equilibrium physics

  1. Stable equilibrium

  2. Unstable equilibrium

  3. Neutral equilibrium

  4. All of the above

Show answer
Correct Option: C
Explanation:

When the center of gravity of a body lies at the point of suspension or support, the body is said to be in neutral equilibrium. Example: rolling ball.If the ball is pushed slightly to roll, it will neither come back to its original nor it will roll forward rather it will remain at rest. This type of equilibrium is called neutral equilibrium.

Which of the following is not a condition of equilibrium?
rotational equilibrium option b: engineering physics motion of system of particles and rigid bodies equilibrium physics
  1. The resultant of all the forces acting on the body should be equal to zero.
  2. The resultant of all the forces acting on the body about the point of rotation should be equal to zero.

  3. Both A and B

  4. None

Show answer
Correct Option: C
Explanation:

Both the above options are conditions for a body to be on equilibrium and for equilibrium, sum of anticlockwise moments about the axis of rotation must be equal to the sum of clockwise moments about the same axis.

Centre of gravity is lowered in _______ equilibrium. Fill in the blank. 

rotational equilibrium option b: engineering physics motion of system of particles and rigid bodies equilibrium physics

  1. Stable

  2. Unstable

  3. Neutral

  4. All of the above

Show answer
Correct Option: A
Explanation:

When the center of gravity of a body lies below point of suspension or support, the body is said to be in stable equilibrium. For example a book lying on a table is in stable equilibrium.

An object is said to be in equilibrium when :
1. There is no resultant force acting on the object.
2. The total clockwise moments about any point is equal to the total anti-clockwise moments about the same point.
3. The object has no energy.

rotational equilibrium option b: engineering physics motion of system of particles and rigid bodies equilibrium physics

  1. 1 only

  2. 2 only

  3. 1 and 2 only

  4. 1, 2 and 3

Show answer
Correct Option: C
Explanation:

An object is said to be in equilibrium when there is no resultant force acting on the object, the total clockwise moments about any point is equal to the total anticlockwise moments about the same point.

Which of the following object is/are in equilibrium?

rotational equilibrium option b: engineering physics motion of system of particles and rigid bodies equilibrium physics

  1. A sleeping cat

  2. A flask resting on a table

  3. A rocking see-saw

  4. A man walking

Show answer
Correct Option: A,B
Explanation:

A sleeping cat, a flask resting on a table and winding a clock are the objects is / are in equilibrium.

The bob of simple pendulum having length l, is displaced from mean position to an angular position with respect to vertical. If it is released, then velocity of bob at equilibrium position : 

rotational equilibrium option b: engineering physics motion of system of particles and rigid bodies equilibrium physics

  1. $\sqrt { 2g\ell (1-cos\theta ) }$

  2. $\sqrt { 2g\ell (1+cos\theta ) } $

  3. $\sqrt { 2g\ell cos\theta } $

  4. $\sqrt { 2g\ell } $

Show answer
Correct Option: A
Explanation:

Potential energy at extreme position = kinetic energy at mean position

$mg\ell (1-cos\theta )=\frac { 1 }{ 2 } m{ v }^{ 2 }$

If the potential energy of the molecule is given by $U = \dfrac {A}{r^{6}} - \dfrac {B}{r^{12}}$. Then at equilibrium position its potential energy is equal to

rotational equilibrium option b: engineering physics motion of system of particles and rigid bodies equilibrium physics

  1. $-A^{2}/ 4B$

  2. $A^{2}/ 4B$

  3. $2A/B$

  4. $A/2B$

Show answer
Correct Option: B

For the equilibrium condition shown. the cords are strong enough to withstand a maximum tension $100 N.$ The largest value of $W $ (in newton) that can be suspended is $W _1$ Find $W _0$ :

rotational equilibrium option b: engineering physics motion of system of particles and rigid bodies equilibrium physics

  1. $25$

  2. $35$

  3. $20$

  4. $60$

Show answer
Correct Option: B

A rope ladder with a length $\ell$ carrying a man ofmass $m$ at its end is attached to the basket ofballoon with a mass $\mathrm { M }$ . The entire system is in equilibrium in the air. As the man climbs up theladder into the balloon, the balloon descends bya height h. Then the potential energy of the man: 

rotational equilibrium option b: engineering physics motion of system of particles and rigid bodies equilibrium physics

  1. Increases by mg $( \ell - h )$

  2. Increases by mge

  3. Increases by mgh

  4. Increases by mg $( 2 \ell - h )$

Show answer
Correct Option: C

A wheel rolling on a horizontal surface is an example of

rotational equilibrium option b: engineering physics motion of system of particles and rigid bodies equilibrium physics

  1. Stable equilibrium

  2. Unstable equilibrium 

  3. Neutral equilibrium 

  4. All of the above

Show answer
Correct Option: B
Explanation:

Neutral equilibrium means that, with a small deviation, the body remains in equilibrium. An example is a wheel rolling on a horizontal surface. If you stop it at any point, the wheel will be in a state of equilibrium. A ball lying on a flat horizontal surface is in a state of neutral equilibrium.