How do machines work (4-2)
Ideal machines
What kind of machines don't exist?
Ideal machines always have
a efficiency as 100%
To overcome the friction of the machine itself.
Force must be applied
By dividing the radius of the wheel by radius of the axle.
How do you figure out the ideal mechanical advantage of a
By dividing the length of the incline by its height.
How do you figure out the ideal mechanical advantage of a inclined plane?
By dividing the distance from the fulcrum to the input force by the distance from the fulcrum to the output force.
How do you figure out the ideal mechanical advantage of a levers?
The length around the threads divided by the length of the screw.
How do you figure out the ideal mechanical advantage of a screw?
By dividing the length of the wedge by its width
How do you figure out the ideal mechanical advantage of a wedge?
The cable system enables you to raise the weights more conveniently by changing the direction to make work easier.
How does a cable system on a weight machine make raising the weights easier?
they both perform work
Ideal and real machines are related because
they both perform work I
Ideal and real machines are related because
don't exist
Ideal machines
a efficiency as 100%
Ideal machines always have
160/80=2
If a machine has input force of 80 and the output force is 160.
The mechanical advantage is 1.
If a machine that changes only the direction of the applied force
Is the force you exert on a machine
Input force
The input force times the input distance
Input work
Always greater than output work.
Input work is
Output force
Is the force a machine exerts on a object
Input force
Is the force you exert on a machine
Input work
The input force times the input distance
Mechanical advantage
The ratio of the output force to the input force
Input work is
Always greater than output work
Output work
.the output force times the output distance
Machine
A device that allows you to do work in a easier way.
Real machines always have
A efficiency lower then 100%
A device that allows you to do work in a easier way.
Machine
The ratio of the output force to the input force
Mechanical advantage
Is the force a machine exerts on a object
Output force
the output force times the output distance
Output work .
Efficiency
Output work/ input work x100
- change the amount of force you exert - change the distance over which you exert a force - change the direction in which you exert a force
Three factors that make work easier because a machine changed 1 of 3.
Force must be applied
To overcome the friction of the machine itself.
It's loss because of Friction
Why are real machines efficiency that way?
It's loss because of Friction.
Why are real machines efficiency that way?
Because friction exists in every machine and reduces the machines efficiency
Why is output work always less than input work in real situations?
Because screwdriver multiples force because you exert an input force on the handle over a greater distance than the output force that is exerted on the tip of the screwdriver.
a screwdriver makes work easier
