3.4.1.2 - Moments Flashcards Preview

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Flashcards in 3.4.1.2 - Moments Deck (13)
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1
Q

Moment =

A

force (N) x perpendicular distance from the point to the line of action of the force (m)

2
Q

In equilibrium what must be equal?

A

cm=acm

3
Q

What is a couple?

A

A pair of equal but opposite coplanar features.

4
Q

What does a couple cause?

A

Doesn’t cause any resultant linear force, but does produce a turning effect.

5
Q

Moment of a couple =

A

force × perpendicular distance between the lines of action of the forces.

6
Q

Weight =

A

mass x gravitational field strength

7
Q

How do you find the centre of mass experimentally?

A
  1. Hang the object freely from a point.
  2. Draw a vertical line downwards from the point of suspension using a plumb bob to get your line exactly vertical.
  3. Hang the object from a different point.
  4. Draw another vertical line down.
  5. The centre of mass is where the two lines cross.
8
Q

What two things does a moment depend on?

A
  • distance from the pivot.

- force applied.

9
Q

What does it mean if a body is in stable equilibrium?

A

When displaced it will return to its equilibrium position.

10
Q

If in equilibrium Fxd

A

= Wb/2

11
Q

In order for something to topple?

A

Fxd > Wb/2

12
Q

What must occur in order for any body to be in equilibrium?

A
  • The resultant force must equal zero.

- The principle of moments must apply.

13
Q

Centre of gravity?

A

The point where the weight of the object appears to act.