Tag: forces - vectors and moments

Questions Related to forces - vectors and moments

The advantages of being short and stocky is that you're less likely to get knocked over. This is because

physics turning effects of forces centre of gravity forces - vectors and moments acceleration due to gravity

  1. The short and stocky person has a lower center of gravity

  2. The short and stocky person has a larger center of gravity

  3. They have less height and less weight

  4. None of the above

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Correct Option: A
Explanation:

Since, short person has lower center of gravity hence it is difficult to knocked them out

Center of gravity is usually located where

physics turning effects of forces centre of gravity forces - vectors and moments acceleration due to gravity

  1. less mass is concentrated

  2. less weight is concentrated

  3. more mass is concentrated

  4. more weight is concentrated

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Correct Option: D
Explanation:

Centre of gravity of an object is a specific point such that the body behaves as if the entire gravitational force is acting only at that point.

Since weight means the gravitational force acting, D is the correct option.
C is not the correct option because, for very large bodies like huge mountains, it is not at the point where more mass is concentrated

Centre of gravity is the point

physics turning effects of forces centre of gravity forces - vectors and moments acceleration due to gravity

  1.  where the weight of the object is supposed to be present or concentrated.

  2.  where the weight of the object is perpendicular to the surface area of the object.

  3. where maximum no of molecules presents

  4. none of the above 

Show answer
Correct Option: A
Explanation:

It is a point on which behaves as if the whole weight of the body appears to be concentrated.

One can lean further to one side or the other without creating enough turning force to tip him over. This is because 

physics turning effects of forces centre of gravity forces - vectors and moments acceleration due to gravity

  1. The person has low centre of gravity

  2. The person has no centre of gravity

  3. The person has high centre of gravity

  4. None of the above

Show answer
Correct Option: A
Explanation:

Center of gravity is the point at which the entire weight of a body may be considered as concentrated so that if supported at this point the body would remain in equilibrium.

One can lean further to one side or other without creating enough turning force to tip him over. This is because the person has low center of gravity as having a low center of gravity decreases the torque hence the person will not tip over.

Statement related to center of gravity that is incorrect is

physics turning effects of forces centre of gravity forces - vectors and moments acceleration due to gravity

  1. The center of gravity of an object is defined as the point through which its whole weight appears to act.

  2. The center of gravity is sometimes confused with the center of mass.

  3. The center of gravity always lies inside the object.

  4. For an object placed in a uniform gravitational field, the center of gravity coincides with the center of mass.

Show answer
Correct Option: C
Explanation:

In case of a ring, the centre of gravity lies at the centre of the ring. Hence option c is the incorrect option

What is the center of gravity of an object?

physics turning effects of forces centre of gravity forces - vectors and moments acceleration due to gravity

  1. The point where gravity appears to act.

  2. The point where gravity doesn't act.

  3. The point where the force of gravity is strongest.

  4. The point where the force of gravity is weakest.

Show answer
Correct Option: A
Explanation:

Option A is the definition of the centre of gravity. B is a contradiction. As far as C ad D are concerned, the force of gravity is equal at all points provided the object is small as compared to the radius of the planet. 

For a bowling ball, how far apart are the center of gravity and center of mass?

physics turning effects of forces centre of gravity forces - vectors and moments acceleration due to gravity

  1. They are at almost exactly the same location.

  2. They are at opposite sides of the object.

  3. They are both at the surface of the object.

  4. They mean the same thing, so they're at the same location, as always.

  5. None of the other answers is correct.

Show answer
Correct Option: A
Explanation:

Centre of mass and of gravity coincide for objects which are small as compared to the radius of the earth.

Note that they don't mean the same thing.

What is the center of mass of an object?

physics turning effects of forces centre of gravity forces - vectors and moments acceleration due to gravity

  1. The mean position of the mass in an object.

  2. The geometric center of an object.

  3. The furthest away position of the mass in an object.

  4. The same as the center of gravity.

  5. The closest position of the mass in an object.

Show answer
Correct Option: A
Explanation:

The mass of the body is scattered equally in all space around the centre of mass. It is closer to the heavier regions of the object and hence need not be at the geometric centre. 

Options C and E don't make sense. 
It doesn't coincide with the centre of gravity for very large bodies like mountains.

Which one of following statements related to center of gravity is incorrect?

physics turning effects of forces centre of gravity forces - vectors and moments acceleration due to gravity

  1. The center of gravity of an object is defined as point through which its whole weight appears to act.

  2. The center of gravity is sometimes confused with center of mass.

  3. The center of gravity always lies inside object.

  4. For an object placed in a uniform gravitational field, center of gravity coincides with center of mass.

Show answer
Correct Option: C
Explanation:

A is the proper definition. In some bodies like hollow bodies, frames and rings, the center of gravity is at the geometric centre where the matter of the object is not present.

The stability of a flexible body depends on:

physics turning effects of forces centre of gravity forces - vectors and moments acceleration due to gravity

  1. height of the center of gravity from the ground.

  2. base area of the body.

  3. shape of the body.

  4. all the above.

Show answer
Correct Option: D
Explanation:

The stability of objects depends on the base, C.G and shape of the body. For a body to be the stable,

  1. The base of the body need to be broad.
  2. The Centre of gravity should be as low as possible.
  3. The vertical line through the center of gravity should fall within the base.