# Pearson’s Edexcel IGCSE Physics Density and Pressure Specification focus questions and answers

## Questions

What is the relationship between density, mass, and volume?

How can you investigate density using direct measurements of mass and volume?

What is the relationship between pressure, force, and area?

How does the pressure at a point in a gas or liquid at rest act?

What is the relationship for pressure difference?

How does the density, gravitational field strength and height affect the pressure difference?

Can you give an example of how to use the relationship between density, mass, and volume in a real-world situation?

How can we calculate the pressure exerted by a force on an area?

Why is pressure difference important to understand?

How can the relationship between pressure difference and density, gravitational field strength and height be applied in a scientific or engineering context?

The relationship between density, mass, and volume is that density is equal to mass divided by volume, represented by the equation: ρ = m/V.

To investigate density using direct measurements of mass and volume, you can measure the mass of an object using a scale and measure its volume by water displacement or by measuring its length, width and height and calculating the volume using the formula V = l x w x h.

The relationship between pressure, force, and area is that pressure is equal to force divided by area, represented by the equation: p = F/A.

The pressure at a point in a gas or liquid at rest acts equally in all directions.

The relationship for pressure difference is: p = h x ρ x g, where p is pressure difference, h is height, ρ is density and g is gravitational field strength.

The density, gravitational field strength, and height all affect the pressure difference, as they are all included in the pressure difference equation.

An example of using the relationship between density, mass, and volume in a real-world situation would be determining the density of a substance to determine whether it will float or sink in a liquid.

To calculate the pressure exerted by a force on an area, divide the force by the area.

Understanding pressure difference is important in various fields such as fluid mechanics, atmospheric science, oceanography, etc.

The relationship between pressure difference and density, gravitational field strength and height can be applied in scientific and engineering contexts, such as designing and analyzing fluid systems, designing of wind turbines, analyzing the atmospheric pressure, etc.