Final Review Flashcards
What is the definition of work?
Work is the transfer of energy when an applied force moves an object over a distance
What is the purpose of simple machines?
To make work easier
What is a pulley, How does it make work easier?
A wheel with a grove for a rope to move the pulley. It makes work easier by changing the direction of the applied force
What is a example of a pulley?
Crane
What is a screw?
An inclined plane wrapped around a cylinder
What is a example of a screw?
Jar lid
What is a wedge?
A modified inclined plane that also increases the distance by which the effort force is applied
What is a example of a wedge?
Axe
What is an inclined plane?
A device that increases the distance by which the effort force is applied
What is a example of a inclined plane?
Ramp
What is a lever?
A board or bar that sits on a fixed point called a fulcrum
What is an example of a lever?
hammer
What is a gear (wheel and axle)?
A wheel with teeth around the perimeter attached to a rod decreases the effort force applied and increases the distance that force is applied over
What is a example of a gear?
Bike wheels
What is the formula for work?
W=FxD
What is the formula for power?
P=W/T
What is the law of conservation of energy?
State that energy can not be created nor destroyed
What is kinetic energy?
Energy that an object possesses due to its motion
What is a example of kinetic energy?
A person walking
A soaring baseball
Wheels on a bike going round and round
What factors impact kinetic energy?
Mass and speed
What is the formula for kinetic energy?
1/2 m x v
What is potential energy?
energy that an object has at rest; stored energy that can be used for later
What is a example of Potential energy?
1.A sling being pulled to its launch position
2.Water behind a dam
3. A yoyo before it is released
4. Energy found in food molecules before eaten
What factors impact potential energy?
the height above the reference point, acceleration due to gravity,mass,
gravitational potential energy
What is the gravitational potential energy formula?
GPE= m x g x h
What are some pros of Nuclear Energy?
Lasts a long time
Clean Energy source
Pays itself back
Creates job
provides continuous electricity
What are the cons of Nuclear energy?
Very high upfront costs
Nuclear waste is bad for the environment and can be radioactive even after it is useful
malfunctions can be catastrophic
Can be stable and unsafe process
What is distance?
How far an object travels or how apart the position are
What is displacement?
Change in position
What is acceleration?
Change in velocity in a given amount of time
What is speed?
The change in distance over change in time
What is velocity?
The change in displacement over a change in time
What is momentum?
A property of a moving system that is equal to its velocity times its mass
What is the formula for velocity?
V= FP - IP / FT - IT
What is the formula for Acceleration?
A= VFinal-VInitial
Explain how a pair of scissors is a compound machine.What kind of simple machine makes a pair of scissors?
A scissor is made up of two or more simple machines making it a compound machine, it uses two wedges and two levers making the machine move side to side.
What is contact?
a force that acts only when on object touches another, examples: normal force
What is a field force?
a force that acts between objects that are not touching
EXamples: electric force, gravitational; force, magnetic force
What is the difference between balanced and unbalanced force?
balanced forces cancel each other out while unbalanced forces cannot cancel each other out
How do you find the net force from two opposing forces?
Subtract the two forces from each other
What is the law of inertia?
that an object at rest remains at rest and an object in motion will remain in motion unless acted on by an unbalanced force
Define Friction
friction is a contact force that works against the motion of a object trying to move past each other
What is friction’s effect on inertia?
Friction stops inertia when the object is in motion
What is the formula for force?
F=ma
How do thermal energies affect phases of matter?
Certain temperatures melt, freeze, boil matter. Most expand when temperature rises and contract when temperature decreases
How is thermal energy transferred?
Convection, radiation, conduction, thermal energy moves from hot to cold
Define Conduction
transfers energy by contact
Define convection
transfers energy by the flow of fluids (air, liquid)
Define radiation
radiation transfers by electromagnetic waves
What is a example of conduction?
spoon in hot water
What is a example of convection?
heat leaves a hot cup when steam rises
What is a example of radiation?
UV Light
What is the formula for thermal energy?
Q=CSPM * T
How does pressure affect fluids (directly)?
Pascals’s Principle: pressure is transmitted throughout the fluid
How does density affect buoyancy?
Density of the object is less than the fluid=will float
Example: oil floats on water
Define viscosity
a measure of a fluid’s resistance to flowing, it is caused by frictions between the particles in the fluid.
What affects viscosity?
Temperature affects viscosity, the higher the temperature the less vicious the substance has
What is the Charles Law Formula?
V1/T1=V2/T2
What is the formula for Gay-Lussac’s law?
P1/T1=P2/T2
What is the formula for Boyle’s law?
P1V2=P2V2
Describe what happens at the particle level when a balloon of gas with a fixed number of particles is heated? How do these particles change affect other properties of gas?
Atoms start to speed up and as they move faster they bump into each other more, this causes more force to be applied to the balloon causing it to expand
What is reflection?
the bouncing of waves off a surface
What is refraction?
the change in wave direction due to a change in wave speed as it enters a new meduim
What is Diffraction?
the bending of a wave around an obstacle or through an opening
What is interference?
the combining of waves where they overlap
What is the difference between mechanical and electromagnetic waves?
Mechanical is a transverse wave and electromagnetic is compressional, mechanical waves require a medium and electromagnetic waves do not need a medium and can be transferred through a vacuum.
Describe the Doppler effect and how it predicts the sound of a passing fighter jet’s engine changes as it flies over your head.
With the Doppler Effect when an object is closer to you, it’s more compressed, and when further away it’s less compressed so the sound of the jet is proportional to how compressed or not compressed a wave is. A more compressed is a higher wave while a lower compressed wave is a lower wave.
Explain the difference between a circuit in series and a circuit in parallel. Include descriptions of voltage drop, current, and circuit operation in your response.
A series circuit flows in one path, with each thing in the circuit connected to the said path. A parallel circuit is all individually connected to the path. This means that if something breaks in a series circuit it all breaks, but in a parallel circuit, the rest of the other things connected to the circuit will remain on. Voltage drop would be the reduction in an electrical current from the source usually by resistors. Current refers to the flow of electricity in a circuit. A circuit is the cyclic path that electricity travels through.
What is the difference between alternating and direct current?
Alternating currents can flow in multiple directions. While direct currents only flows in one direction.
What are example of how alternating and direct currents are used?
Ac is used to deliver power to houses, office buildings, etc. DC is used in battery-operated objects.
What is static electricity?
The accumulation of extra electrons on an object
Define voltage
The force that moves electric charge carriers through an electrical circuit.
Define parallel and series circuit
Series Circuit-a circuit with only one path that electric currents can take
Parallel circuit-a circuit with multiple paths that electric current can take
What is the difference between a series and parallel circuit and how they are used?
A series circuit all flows through one path if there is a break in the circuit all of them go out. A parallel circuit, everything is connected back to the original power circuit so if one goes out none of the others will go out. An example of a series circuit is Christmas lights and a example of a parallel circuit is the wiring in your house.
What is the formula for current?
I=V/R
