Pressure in Fluids and Upthrust

This page focuses on fluid pressure and upthrust concepts, which are crucial in understanding how objects behave in liquids and gases.

The page begins by defining a fluid as either a liquid or a gas. In fluids, pressure is caused by particles colliding with either an object or the walls of the container.

Highlight: In a column of liquid, pressure is highest at the bottom due to the greater weight of the liquid above.

The density of the liquid also affects pressure, as denser liquids have more particles creating additional weight.

The concept of upthrust is then introduced:

Definition: Upthrust is the upwards force exerted by a fluid on a submerged object.

The page explains the conditions for floating and sinking:

• An object floats when its weight equals the upthrust
• An object sinks when its weight is greater than the upthrust

Archimedes' Principle is also explained:

Definition: The upthrust exerted on a body immersed in fluid equals the weight of the fluid the body displaces.

This principle helps explain why dense objects sink while less dense objects float. Dense objects do not displace enough fluid to equal their weight, so they sink, and vice versa.

Speed, Velocity, Distance, and Displacement

This page covers the fundamental concepts of speed, velocity, distance, and displacement, which are essential for understanding motion in physics.

The page begins by differentiating between speed and velocity:

Definition: Speed is how fast an object is travelling (scalar), while velocity is the speed of an object in a given direction (vector).

It's noted that when travelling in a straight line with constant speed, an object will have a constant velocity. However, when travelling in a circle, velocity is constantly changing, resulting in acceleration.

Example: An object orbiting a planet has a constantly changing velocity, even if its speed remains constant.

The page also explains that when turning a corner, speed may stay the same, but velocity changes due to the change in direction.

Next, the concepts of distance and displacement are introduced:

Definition: Distance is how far an object moves (scalar), while displacement is how far an object moved and in what direction (vector).

The page briefly mentions the concept of resultant force, which occurs when more than one force acts on an object. This ties back to the earlier discussion on vector diagrams.