gensci, term exam

Law of Inertia

• if an object is at rest, it’ll stay at rest, unless a net force acts on it.

Law of Acceleration

• more force = more acceleration

Law of Action and Reaction

• action there is an equal and opposite reaction.

Gravity

• force that attracts all objects with mass or energy towards each other.

Work

• done when a force applied to an object causes displacement of the object.

Energy

• capacity to do work

Power

• work done per unit of time

Force

• pushing and pulling

Mass

• amount of matter

Weight

• affected by gravity

Heat Transfer

• flows from hotter to colder objects to achieve equilibrium

Conduction

• transfer of heat through direct physical contact

Convection

• transfer of heat through movement of fluids

Radiation

• transfer of heat through electromagnetic waves

Zeroth Law

• temperature equality, two bodies are each with a third—they’re in equilibrium

First Law

• energy remains constant, cannot be created nor destroyed

Second Law

• entropy increases in isolated systems, heat flows from hot to cold

Third Law

• entropy approaches a constant value as temperature approaches absolute zero

Motion

• change in position of an object over time

• involves object’s displacement, distance traveled, speed, velocity, and acceleration

Translational Motion

• motion of an object from one location to another without rotating

• moves along a path

• all parts move in parallel

• can be rectilinear or curvilinear

Rotational Motion

• motion of an object around a fixed axis or point

• circular motion around the axis

• object rotates or spins

• can be internal or external

Combination Motion

• when an object experiences two or more types of fundamental movements simultaneously

Linear Quantity

• describes how far an object travels and how fast

Displacement (d)

• change in position of an object (direction)

Velocity (v)

• speed with a direction (vector)

Acceleration (a)

• the rate of change of velocity

Cause of Motion: Force (F)

• push or pull applied on an object in a straight/curved path

Angular Quantity

• describes how objects spin or rotate along a fixed axis, or their rotational motion

Angular Displacement (theta)

• change in the angle (in radian)

Angular Velocity (omega)

• rate of change of angular displacement

Angular Acceleration (alpha)

• rate of change of angular velocity

Cause of Motion: Torque (t)

• rotational equivalent of force

Machine

• device that uses power to apply forces and control movement to perform a specific task

Simple Machine

• mechanical device that changes the direction or magnitude of a force

• few or no moving parts to modify

Inclined Plane

• sloping plane tilted at an angle, with one end higher than the other

Wheel & Axle

• circular wheel attached to a rod (axle)

• make work easier by moving objects across distances

• reduce the friction involved in moving an object

Pulley

• made with a wheel and a rope or cable

• cord wraps wheel around

• used to change the direction of the force

Lever

• board or bar (arm) that rests on a support (fulcrum)

• exerting force on one end creates force on the other end

3 TYPES OF LEVER

F - FIRST CLASS

L - SECOND CLASS

E - THIRD CLASS

Screw

• kind of inclined plane, wrapped around a pole

• hold things together or lift objects

Wedge

• double inclined plane

• break apart substances by applying force

Compound Machine

• consists of two or more simple machines put together

• do more difficult jobs

Machine Efficiency

• measure of how well a machine converts the input work (or energy) into useful output work

High Mechanical Advantage

• machine multiplies the input force effectively

• ratio of output to input force

• efficient machines have high MA = small effort force lift heavy loads

Fluid

• any substance that can flow and take shape of its container

enclosed

• trapped/sealed

incompressable

• not that easy to squeeze

Blaise Pascal

• did the barrel experiment (filled with water and enclosed, attached to a narrow tube on top, added water-level, and pressure rose, then the barrel bursted)

Pressure

• applied to an enclosed, incompressible fluid, it is transmitted through out the fluid and to the walls of the containing vessel

Archimedes’ Principle

• buoyancy force on an object immersed in the fluid is equal to the weight of the fluid displaced by the object

Buoyancy

• upward force exerted by a fluid that opposes the weight of an immersed object

Density

• a measure of how compact and tightly packed matter is within a specific space

Mass

• influences the object’s weight (downward force)

Volume

• directly increases the volume of displaced

Fluid

• increasing buoyant force (upward force)

Shape

• drastically influences the volume for a fixed mass

Conductors

• allows the flow of electricity (charged)

Inductors

• blocks or resists electricity

Electricity

• generated by the movement of electrons between atoms

Current (I)

• flow rate of electricity

• measured in Ampere (A)

Voltage (V)

• electrical pressure/push that forces current to flow

• measured in Volts (V)

Resistance (R)

• opposition to the flow of electric current in a circuit

• slows down or limits how much electricity can flow

• measured in ohms

• generates heat (Joule heating)

Simple Circuit

• battery (source), consumer (load), switch (control), and path

Power (P)

• rate at which electrical energy is consumed or generated

• measured in watts (W)

!! not all power is converted into useful work (electrical resistance)

Electrical Hazards

• dangerous conditions that could lead to injury/death

Overloading

• when too much current flows through a wire/circuit

Damage Insulation

• exposing live wires due to heat melting insulation

Damp Electrical Conditions

• increases risk of electrocution

Faulty Wiring

• exposed conductors, short circuits

Electrocution

• severe electrical shock

lighting

• incandescent bulbs

heating/cooling

• poor house insulation

appliances

• phanton loads (vampire power)