physics assesment

pressure: the perpendicular component of a force on a surface divided by the surface’s area

  • preasure of a fluid is due to the weight of the fluid on a contained area.

  • the preasure of the fluid depends on the density of the fluid and the depth and the g but not in the volume or area of the container.

    ✅ Pressure Formula (in Fluids):

    P=ρ×g×hP = ρ × g × h (ρ → density) pa

    Force = Pressure × Area

    ✨ Formula:

    F=P×AF = P × A F=Newton p= pascal a=m2

  • pascals principle: in a closed fluid the preasure applied to any point is transmited undiminished (without loss) to all particles of the fluid. (for hydronic press)

✅ Pascal’s Law Formula:

P1=P2P₁ = P₂

Since pressure is transmitted equally:

P=F/AP = F / A

So you can write:

F1/A1=F2/A2F₁ / A₁ = F₂ / A₂

buoyant force: is the upward force by a fluid when an object is emersed in it.

🧠 Easy Tip to Remember:

"Emersed" = Exposed. (E for E)

  • Emersed = What you see sticking out of the water

  • Displaced = The amount of water moved because of what’s in it

we can use a spring scale

Fb = scale reading in air - scale reading in fluid.

Fs = Fg btw Fs is scale reading in air

Archimides Principle:

the weight of the displaced fluid = the buoyant force acting on an object emersed in that fluid.

Fb = weight of the diplaced fluid

🧮 Want the Formula?

BuoyantForce(Fb)=ρfluid×g×VBuoyantForce(Fb)=\rho fluid\times g\times V

Fnet = FB - Fg

objects will float if the density of the object is less than the fluid

float:

ρ\rho object < ρ\rhofluid → its equal and at rest, has less volume =more density

suspended:

💡 What does "Suspended" mean?

An object is suspended in a fluid when it neither sinks nor floats — it stays in the middle, just hanging there!

ρ\rhofluid = ρ\rhoobject → Fg = Fb so more volume and less density

sinking:

ρ\rhoobject > ρ\rhofluid → Fb + N = Fg

💡 What does "Submerged" mean?

Submerged means completely under the surface of a fluid (like water).

Fg=Fg = ρobject⋅g⋅v\rho object\cdot g\cdot v

Fb+T=FgFb+T=Fg

Bernoulli’s principle: when pressure exerted by the fluid increases velocity of the fluid decreases

  • When the temperature of a liquid is lowered, the average kinetic energy of the particles decreases, and the cohesive forces have more effect.

For many solids, the particles become frozen into a fixed pattern called a crystal lattice.

crystal lattice: the particles of a solid arranged in a fixed paattern. bcz of cohesive forces.

  • The particles in a crystalline solid do not stop moving completely. Rather, they vibrate around their fixed positions.

In other materials, such as butter and glass, the particles do not form a fixed crystalline pattern.

Such a substance, which has no regular crystal structure but does have a definite volume and shape, is called an amorphous solid.

  • External forces applied to a solid object may twist or bend it out of shape.

The ability of a solid object to return to its original form when the external forces are removed is called the elasticity of the solid.

  • Elasticity depends on the electromagnetic forces that hold the particles of a substance together.

  • If too much deformation occurs, the object will not return to its original shape, because its elastic limit has been exceeded.

  • When a solid is heated, the kinetic energy of the particles increases.

  • They vibrate rapidly and move farther apart, weakening the attractive forces between the particles.

  • Thermal Expansion of Solids As a result, when the particles vibrate more violently with increased temperature, their average separation increases, and the solid expands.

  • The change in length of a solid is proportional to the change in temperature and to its original length.

  • Different materials expand at different rates.

  • The coefficient of linear expansion (α) is equal to the change in length of a solid, divided by its original length and the change in temperature.

α=ΔLLi⋅ΔT\alpha=\frac{\Delta L}{Li\cdot\Delta T}

  • The unit for the coefficient of linear expansion is 1/°C, or (°C) −1.

Since solids expand in three directions, the coefficient of volume expansion (β) is about three times the coefficient of linear expansion.

The coefficient of volume expansion is equal to the change in volume of a solid divided by its original volume and the change in temperature.

β=ΔVvi⋅ΔT\beta=\frac{\Delta V}{vi\cdot\Delta T} , β=3α\beta=3\alpha

The unit for β is 1/°C, or (°C)−1.