Density, Pressure, Upthrust - Assesment 2 Flashcards
(16 cards)
What is the formula for density?
Density (ρ) = Mass (m) / Volume
What are the standard units of density?
kg/m³ or g/cm³
How can you measure the density of an irregular object?
Use a displacement can to find the volume, and a balance to measure the mass, then apply the density volume
How does temperature affect density?
Increasing temperature reduces density because substances expand, increasing their volume
What happens when two substances of different densities are mixed?
The denser substance sinks and the less dense substance floats
What is the formula for pressure?
Pressure (P) = Force (F) / Area (A)
What are the units of pressure?
Pascals (Pa), where 1 Pa = 1 N/m²
How does pressure change with area?
Larger area → lower pressure (e.g. snowshoes)
Smaller area → higher pressure (e.g. sharp knife)
Why do sharp objects like knives and nails have small surface areas?
To increase pressure, making it easier to cut or penetrate materials.
How does pressure in gases work?
Gas molecules move randomly and collide with surfaces, exerting pressure.
What is upthrust (buoyant force)?
The upward force exerted by a fluid on an object
State Archimedes’ Principle
The upthrust on an object is equal to the weight of the fluid displaced by the object
What determines whether an object floats or sinks?
If upthrust = weight → object floats
If upthrust < weight → object sinks
Why does a boat float even though it’s made of dense materials like steel?
The shape of the boat increases the volume of water displaced, providing enough upthrust to support its weight
How does pressure in a liquid change with depth?
Pressure increases with depth because there is more fluid above, exerting force
How does pressure act in liquids?
PRessure in liquids acts equally in all directions
