Tag: option b: engineering physics

Questions Related to option b: engineering physics

The resultant moment of all the forces acting on the body about the point of rotation should be

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

  1. Greater than one

  2. Smaller than one

  3. Zero

  4. One

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Correct Option: C
Explanation:

The resultant moment of all the forces acting on the body about the point of rotation should be zero, i.e., the sum of the anticlockwise moments about the axis of rotation must be equal to the sum of the clockwise moments about the same axis.

In neutral equilibrium,

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

  1. center of gravity is neither raised nor lowered.

  2. center of gravity is raised .

  3. center of gravity is lowered.

  4. None

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Correct Option: A
Explanation:

It's center of gravity is neither raised nor lowered. This means that its center of gravity is at the same height as before this type of equilibrium is known as neutral equilibrium.

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

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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

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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

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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

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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

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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 } $

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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. $A/2B$

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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. $60$

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Correct Option: B