Chapter 10 - Pressure, Gravity And Moments

Question 1

Define:

pressure

Answer 1

force per unit area

Question 2

Define:

The Pascal

Answer 2

The unit of pressure is the Pascal

1Pa = 1N per square metre

Question 3

Define;

buoyancy force/ upthrust

Answer 3

Because pressure increases with depth the pressure underneath is greater than the pressure on top. The liquid therefore exerts an overall upward force on the body.

Question 4

Defining

moment of a Force

Answer 4

Force x perpendicular distance

Question 5

Define;

Levers

Answer 5

A rigid body which is free to rotate about a fixed point is called a lever

Question 6

Define couple

Answer 6

To parallel forces with the same attitude afternoon upset directions is called a couple

Question 7

Define;

torque

Answer 7

The moment of a couple is equal to Torque

Question 8

State Archimedes principle

Answer 8

States that when an object is partially or completely immersed in the fluid experiences and upthrust equal in magnitude to the weight of the fluid displaced.

Question 9

State The Law of flotation

Answer 9

States that the weight of the floating body is equal to the weight of the fluid it displaces

Question 10

State Boyles Law

Answer 10

States that at constant temperature the volume of a fixed mass of gas is inversely proportional to its pressure

Question 11

State newtons law of universal gravitation

Answer 11

States that any two point masses in the universe attracted to each other with a force that is directly proportional to the product of the masses and inversely proportional to the square of the distance between

Question 12

State the conditions for equilibrium of a body

Answer 12

When the body is at rest
The vector sum of the forces in any direction is zero
The sum of the moments about any point is zero

Question 13

Define:

Density

Answer 13

The density of a substance is its mass per unit volume