science test: oct 30th Flashcards
what is a simple machine?
anything that reduces or changes the direction of the force that must be applied to move any object.
what are the 6 simple machines?
- inclined plane (ramp)
- wedge
- screw
- lever
- wheel and axle
- pulley
what is an inclined plane?
a tilted flat surface ex. ramp.
how do we use it?
wheelchair access.
what is a wedge?
a modified incline plane that can be moved with force
what is an example and what is a description of what it does? (wedge)
ex. knife, it cuts food.
what is a screw (Archimedes) screw?
an incline plane that can be cut into a central core.
what is an example and what is a description of what it does? (archimedes screw)
ex. a screw, it holds things together.
what is a lever?
a lever is a rigid bar that pivots at a point called ‘fulcrum’ -
what is an effort arm?
part of bar between the fulcrum and where the effort is applied.
what is a load arm?
a load arm is the section between fulcrum and object you want to move.
what is the first class of levers?
fulcrum between the load core and input force ex. teeter totter
what is the second class of levers?
load force (dirt) is between the fulcrum and the input force (person) ex. wheel barrow
what is the third class of levers?
input force (lifting the fish pole) is between fulcrum (person) and the load force (fish)
what is an example of a wheel and axel- gear?
doorknob -
wheel = doorknob
axel = shaft
turning motion is transferred to another part of the system, making the work easier
ex well (turning the handle raises the bucket)
what does a pulley have to do with wheels and axels???
uses wheels and axels to make lifting/moving large heavy objects easier, more pulleys easier the task.
what is a force?
a force is a push or pull upon an object resulting from the objects interaction with another object. whenever there is an interacting between two objects, there is a force upon each of the objects. when the interaction ceases, the two objects no longer experience the force. forces ONLY exist as a result of an interaction.
what are the 8 types of forces?
gravitational, magnetic, electrical (aka electricity), mechanical force, frictional (aka tensile), compressive, rotational.
what is gravitational force?
pull of the earth downward an object, everything falls at same rate if there was no resistance 9.8 m/s.
what is a magnetic force?
magnetic push (north to north, south to south) or pull (north to south, south to north.
what is an electrical force?
static cling, static electricity, electric current, lightning.
what is a mechanical force?
muscular, hurricane, punch, slapshot, rubbing, abrasion, resistance.
what is a tensile force?
tightening.
what is a compressive force?
crushing, squeezing, grip.