# 1.2.3 EQUILIBRIUM

HideShow resource information
What is the centre of gravity of an object?
Point where the entire weight of an object appears to act
1 of 15
Describe an experiment to find the centre of gravity of an object
1. Hang object freely from a point // 2. Hang plumb line from the same point and draw vertical line from point of suspension // 3. repeat 2/3 times until lines cross // 4. centre of gravity is where lines cross
2 of 15
What is a couple?
pair of forces that tends to produce rotation only
3 of 15
What is a torque of a couple?
product of one of the forces and the perpendicular distance between them
4 of 15
How do you calculate the torque of a couple?
one force x perpendicular distance between
5 of 15
What is the moment of a force?
magnitude of a force multiplied by the perpendicular distance from the point to the line of action
6 of 15
How do you calculate a moment of a force?
force x perpendicular distance from pivot / axis / point
7 of 15
Describe a couple
pair of equal and opposite forces that tend to produce rotation only // lines of action do not intersect // cannot produce a resultant force
8 of 15
What is equilibrium?
when an object is at rest or travelling with a constant velocity because net force and moment both = 0
9 of 15
Describe a body in equilibrium
object does not change in it's motion // acceleration 0 // resultant net fore, linear acceleration, resultant net moment and anger acceleration is all 0
10 of 15
What is the principle of moments?
the sum of the clockwise moment about a point is equal to the sum of the anti-clockwise moments about the same point
11 of 15
What is density?
the mass per unit volume of a substance
12 of 15
What does density depend on?
mass of each of its atoms // the way the atoms are packed together
13 of 15
What is pressure?
'normal' force per unit area acting on a surface
14 of 15
What is a pascal?
measure of pressure, newton per metre^2
15 of 15

## Other cards in this set

### Card 2

#### Front

Describe an experiment to find the centre of gravity of an object

#### Back

1. Hang object freely from a point // 2. Hang plumb line from the same point and draw vertical line from point of suspension // 3. repeat 2/3 times until lines cross // 4. centre of gravity is where lines cross

### Card 3

#### Front

What is a couple?

### Card 4

#### Front

What is a torque of a couple?

### Card 5

#### Front

How do you calculate the torque of a couple?

## Similar Physics resources:

See all Physics resources »See all Forces resources »