Mechanics and Thermal Physics Review

Flashcards based on Mechanics and Thermal Physics lecture notes for exam preparation.

What formula represents the direct relationship between force, mass, and acceleration, as stated in Newton's 2nd law?

F = ma

What two conditions must be met for an object to be in equilibrium?

Resultant force = 0 and Resultant moment = 0

What factors contribute to the stability of an object?

Lower center of mass and Wider base

What does the area under a speed-time graph represent?

Distance traveled

What formula is used to calculate pressure in fluids?

P = ρgh (where ρ is density, g is gravity, and h is height)

What force is necessary for circular motion?

Centripetal force (Fc)

How does speed affect centripetal force?

Centripetal force is directly proportional to speed.

What are the formulas for Kinetic Energy and Gravitational Potential Energy?

Kinetic Energy (K.E) = 1/2mv² and Gravitational Potential Energy (GPE) = mgh

What is the distinction between elastic and plastic deformation of solids regarding exceeding the elastic limit?

Elastic deformation returns to its original shape; plastic deformation does not once the force is removed.

According to Newton's Second Law, how is force related to a change in momentum over time?

F = Δp/t (Force equals the change in momentum divided by time).

What is the law of conservation of momentum?

Total momentum before a collision is equal to the Total momentum after a collision in a closed system.

List two advantages of using wind energy.

Renewable and environmentally friendly

List two disadvantages of using nuclear energy.

High cost and radioactive waste

What are the three states of matter and how do their particle spacing and forces compare?

Solid (close spacing, very strong forces), Liquid (loose spacing, strong forces), Gas (far apart spacing, weak forces)

What is temperature a measure of?

Average Kinetic Energy (K.E)

How does conduction transfer thermal energy, and provide an example of a material where this works well.

Through direct contact, where heat flows from warmer to cooler objects. Metals are good conductors.

Describe how convection currents work to transfer heat in fluids.

Hot rises, cold falls, creating a circulating current that transfers heat.

How does radiation transfer heat, and what medium is required?

Via electromagnetic waves (infra-red). Radiation does not require a medium and can travel in a vacuum.

During a change in state, what happens to the heat energy, and does the temperature change?

All the heat energy is used to break the bonds, so the work is done, potential energy increases, and kinetic energy and temperature remain constant.

What factors affect the rate of evaporation?

Temperature, surface area, air currents, and humidity

What are the key differences between evaporation and boiling?

Evaporation occurs only at the surface and at any temperature without bubbles, while boiling occurs throughout the liquid at a specific temperature with bubbles.

If light is reflected in a plane mirror, what is the relationship between i and r.

Angle of incidence = Angle of reflection

What type of wave are sound waves?

Longitudinal waves

How does the speed of sound vary across solid, liquid, and gas?

Speed of Sound - Solid > liquid > Gas

What happens to the speed and wavelength of light as it moves from a less dense to a more dense medium?

Velocity decreases & wavelength descreases

How is the refractive index (n) be calculated?

n= speed of light in air/ speed of light in medium = sin(angle in air) / sin (angle in medium)

Mention the uses of Microwaves

Bluetooth and Wifi, penetrate walls

How does a convex lens correct long sightedness?

Causes rays to meet on the retina.

How does a concave lens correct short sightedness?

Causes rays to meet on the retina.

What are the three main properties of an image formed by a magnifying glass?

Virtual, upright, and larger in size

List the reasons for taking safety precautions when handling radioactive sources.

Lead lined overall, wear gloves & long forceps, minimise exposure time, and store in labeled lead box.

Define Isotopes

Atoms of the same element, Same proton number, different mass number

What are the three types of radioactive decay?

Alpha (α), Beta (β), and Gamma (γ)

What is half-life?

The time required for half of the undecayed nuclei to decay.

List three natural sources of background radiation.

Cosmic rays from the sun, Radon gases from rocks and atmosphere, and fossils underground.

What type of devices/applications do we use short ariel?

Mobile phones and Satellites

What is earthing?

When the charged wire sends the charges to earth

State the factors affecting resistance.

R ∝ L, ρ(resistivity), Material, Temperature

Which device measures current?

Ammeter connected in series.

What factors affect the speed of rotation in DC motor?

Increase current, Stronger magnet, increase number of turns

What are the advantages of Electricity transmission at high voltage?

Low current, low heat losses