4 Forces Density and Pressure

Question 1

Define

Centre of gravity

Answer 1

The point at which the weight of the object may be considered to act

Question 2

What does a couple consist of?

Answer 2

Equal in magnitude
Opposite in direction
Perpendicular to the distance between them

No resultant force

Question 3

State

Principle of moments

Answer 3

For a system to be in equilibrium, the sum of clockwise moments about a point must be equal to the sum of the anticlockwise moments (about the same point)

Question 4

Conditions for equilibrium

Answer 4

There is no resultant force
There is no resultant torque

Question 5

Define

Density

Answer 5

mass per unit volume

Question 6

Define

Pressure

Answer 6

Force per unit Area

Question 7

Define

Couple

Answer 7

A pair of equal and opposite forces that have equal magnitude and opposite directrion applied to a body in parallel but not along the same line

Question 8

Define

Upthrust

Answer 8

a force which pushes upwards on an object submerged in a fluid (liquids and gases)

Question 9

State

Archimedes Principle

Answer 9

An object submerged in a fluid at rest has an upward buoyancy force (upthrust) equal to the weight of the fluid displaced by the object