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Terms in this set (65)
What is work?
Applyinh a force to an ovject so thst it moved IN THE sAmé DIRECTION as ghe applied force
What is the work equation?
Force x distance (w= fd)
What is the SI unit for work (label)
1 Joule= _____
Work is 0 when
an object is not moving
What is power?
the rate at which work is done
What is the equation for power?
What's the SI unit (label) for power?
1 J/s (joule/second)
Machines make work easier by changing _______
The force needed to do the work
Decreases force needed (and vise versa)
What do machines do?
multiply and redirect forces
What is mechanical advantage?
Measure of how much a machine multiplies force (or distance) (how much a machine helps your life)
The larger the number the _______ the mechanical advantage
What is the equation for mechanical advantage
Input distance Output force
——————————- = ————————
Output distance Input force
Input= what YOU do (human)
Output= what the MACHINE does (machine)
What are simple machines?
Simple devices without moving parts that can make up more complex machines
What are the 6 types of simple machines
Inclined Plane, Wedge, Screw, Lever, Wheel and Axle, and Pulley
Levers have an arm that turns around a point called a
What is a class 1 lever and give an example
🔺(fulcrum or pivot point)
Example: see-saw or hammer
What's a class 2 lever and give an example
or pivot Effort
Example: wheel barrow
Pulleys are a form of
What's a class 3 lever and give an example
(fulcrum | effort (in the middle)
Example: your arm (the fulcrum is the muscle, the effort is your elbow or shoulder and the load is the weight)
Using more than one pulley __________ the mechanical advantage
A wheel and axel is a ______ or ________ connected to a shaft
Lever or pulley
When the wheel is turned so is the
An inclined plane turns a _______ ________ force into a ___________ __________ force by spreading the work over a large distance
Small input force into a large output force
Quick magic trick with inclined planes turning into wedges
\| + |/
🔺+🔺 (two inclined planes)
🔻 (WEDGE AGAIN)
Wedges turns single downward force into
Two forces directed out
Inclined plane wrapped around a cylinder
What is a compound machine
a machine that combines two or more simple machines
What is energy
The ability to do work
Ok quick turn over the flash card
You're gonna do great on the test stop stressing I can FEEL you stressing from my house
Whenever work is done, ______ is transformed or transferred to another system.
SI unit for energy (label)
What is potential energy?
What is gravitational potential energy?
Stores energy determined by an objects position with respect to the ground
What is the potential energy equation
What is kinetic energy
energy of motion
What is the equation for kinetic energy
KE= 1/2MV^2 (m= mass, V= speed (velocity?))
Can KE change to PE
Yes and vise versa
sum of the potential energy and kinetic energy in a system
What is non-mechanical energy?
Atomic; does not affect motion on a large scale
What is chemical energy and examples
Energy stored in that bonds of chemical compounds
•living things getting energy from the sun
What is nuclear fusion?
H atoms combine to produce energy in the sun
Nuclear energy is a result of what?
Nuclear fission= slitting atoms to release energy
What is electrical energy
The movement of electrons
What is light energy?
The movement of waves
What is sound energy
Vibration of air molecules
What is thermal energy
Kinetic energy of atoms
Can energy change to other forms or objects?
Heat and sound
Energy can be created or destroyed (T or F)
False, it cannot be created or destroyed it just changes forms
At any given time, the total energy should be ______
What is a closed system
Doesn't exchange energy with surroundings
What is an open system
Exchanges energy with surroundings
For any system, the net change in energy=
The energy transferred as work and as heat
Is all work done by machines useful
What is efficient?
It wastes little
What is the equation for efficiency
Useful work out/total work put in
How to you express answers as a percentage
Multiply by 100%
Are any machines 100% efficient?
No because of friction
What are perpetual machines
A machine designed to keep going forever without any input of energy
Are perpetual motion machines possible?
_______ leaks out of a system
What do machines always need?
An input of energy
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