Unit 4 Flashcards
what is work
ex. when you exert a force on an object and move that object some distance in the direction of the force you do work on the object.
the transfer on energy through motion
what is the formula for work
work = force times distance
what is work measured in
it is measured in units called joules
what is mechanical advantage
comparison of the force produced by a machine to the force applied to the machine
what is one key thing you should
know about mechanical advantage
the smaller the effort force compared to the load the greater the mechanical advantage.
what is the formula for mechanical advantage (Newtons )
Load arm/Effort force
what is the formula for mechanical advantage in (Cm or M)
Effort arm/ load arm.
what is speed ratio
the relationship between the speed rotations of a smaller gear and a larger gear is called the speed ratio
what is the formula for calculating speed ratio
Number of driver gear teeth/ Number of follower gear teeth
what are the 4types of pulleys
fixed pulley
movable pulley
block and tackle
compound pulley
what is a pulley
is a grooved wheel with a rope or a chain running along the groove.
the axle of the pulley acts like a what?
a fulcrum
what is a fixed pulley
is attached to something that does not move such as a ceiling.
what is a movable pulley
is attached to something movable
what are a block and tackle
a pulley system that is a combination of fixed and movable pulleys
what is a compound pulley
a combination of several pulleys working together
what is pascals law
change of pressure is transmitted evenly throughout a fluid
what is a hydraulic lift
is a mechanical system that raises heavy objects
what is a hydraulic lift used an?
a hydraulic lift uses fluid under pressure in a closed system.
what is a closed system
a system having a boundary that separates it from its surroundings
what is a example of a closed system
your body’s circulatory system
what is the formula for pressure
Force/Area
what does Pascals law states
pressure is transmitted unchanged throughout the liquid
what is one pascal of pressure in newtons
it is a force of one newton per square meter
what is a hydraulic system?
a device that transmits an applied force through a liquid to move something else by means of pressure
what are the two essential characteristics of a hydraulic system?
their incompressibility and their ability to transmit pressure
what is a Pneumatic system?
a system in which a gas, such s air transmits a force exerted on the gas in an enclosed space
what is an example of a hydraulic system in your body?
Our heart is an amazing hydraulic device
what is an example of pneumatic system in our body?
the respiratory system in our body is a example of a pneumatic system because of the air entering and leaving the lungs.
what is a subsystem?
when a simple machine is apart of a large system we call it a subsystem
what is a simple machine ?
a single lever, a pulley, or a wheel and axle is a simple machine.
what are the three combinations of levers in the backhoe?
called the boom, the dipper, and the bucket
What type of class lever is the boom in the backhoe? and what is its job?
it is a class 3 lever that raises or lowers the dipper
what type of class is the dipper and what is its job?
It is a class 1 lever that moves the bucket in and out.
what is the bucket’s job and what type of class lever is it?
it is a class 1 lever that tilts to dig a hole and then empty its load of dirt or other material.
what is a backhoe?
is a rotating assembly of three levers combined with a hydraulic system.
what is kinetic energy?
the energy of motion
what is an example of kinetic energy?
when you are moving the pedals of a bicycle, the motion of the pedals are called Kinetic energy
what is potential energy?
Is stored energy
what is an example of potential energy ?
our body is an example of potential energy
what does the Internal combustion engine describe?
the way the engine works
how many cylinders do Internal combustion engines usually have?
four, six, or eight pistons and cylinders.
what are all the four steps of the Internal combustion engine?
- Intake stroke
- Compression stroke
- Power stoke
- Exhaust stroke
what is the Intake stroke of Internal combustion engine?
the piston moves down the cylinder and draws in the fuel-air mixture fine droplets of gasoline mixed with air
what is the Compression stoke in the Internal Combustion engine?
it is where the piston moves up. The fuel-air mixture is compressed into a smaller space.
what is the power stoke in the Internal Combustion engine?
it is when the piston is almost at the top and a spark from the spark plug ignites the mixture Hot gases expand forcing the piston down. Energy is transferred from the piston to the wheels of the car.
what is the exhaust stoke in the Internal Combustion engine?
the piston moves up again, compressing and pushing out the waste products left over from burning the fuel-air mixture.
what is a hydrogen fuel cell?
a cell that fuels chemical reaction that uses hydrogen and oxygen from the atmosphere to make electricity
what is a crankshaft?
a shaft that turns or is turned by a crank. a crank shaft turns the wheel of a automobile.
what is a piston?
in a engine a disc shaped part that fits tightly inside a cylinder in which some force, such as steam pressure moves it back and forth or up and down
what is a class 1 lever
is a lever in which the fulcrum is between the effort and the load
what is the class 2 lever
a lever in which the load is between the fulcrum and the effort ex. Bottle opener
what is a class 3 lever
a lever in which the effort is applied between the fulcrum and the load. eg. tweezers
