Mechanical Systems Flashcards
what is a lever
a simple machine that you use to exert a force on an object in order to move it
what is a fulcrum
the fixed point that supports the lever. the lever rotates around the folcrum
What is the effort force
the force supplied to any machine to produce movement/action
what is the load
the mass of an object that is moved or lifted by a machine
what is the effort arm?
it is the distance between the fulcrum and the effort force
what do we call the distance between the fulcrum and the load
the load arm
what are the three classes of lever
Class 1 = the fulcrum is between the effort and the load (like a seesaw)
Class 2 = the load is between the fulcrum and the effort (wheelbarrow)
Class 3 = the effort force is between the fulcrum and the load (hockey stick or baseball bat)
What type of lever are most of the levers in your body?
Class 3
What is canada’s most interesting outerspace lever?
The Canadarm (The Space Shuttle Remote Manipulator System). It functions much like a human arm.
What is work?
Work = force X distance
How is work measured?
work in measured in joules
When you lift one newton a distance of 1 m you have done 1 joule of work
What is an inclined plane?
A slope that reduces the force needed to lift something
Suppose that you are a passenger in a SUV gets stuck in the mud. You and the driver use a tree branch to pry the back end out of the mud with both of you pushing on the same end over another tree. (like a class 1 lever) If the truck has a load force of 2500 N and you and the driver apply an effort force of 500N, what would the mechanical advantage be?
5
To lift a quad out of the mud, you decide to use a thick branch as a lever. The entire branch is 1.5m long and you rest the branch on a log so that 0.5m is under the edge of the trailer. You are able to push down on the other end of the branch with a force of 300N. What is the maximum force you would apply to the trailer?
600N
A grocery store clerk is trying to convince the manager that he deserve a raise because he does more work than the clerk who brings carts into the store. In one hour, the clerk lifts each 10kg bag from a pallet of 50 bags onto a shelf 1.5m off the floor, and the clerk who moves the carts pushes 25 carts each weighing 7kg a distance of 10m from the parking lot into the store. Who does more work, and by how much?
The clerk who moves the cart by 10 000 Joules
What is the effect on work when Mechanical Advantage is greater than one
work is easier
There are many examples of levers in the human body. Your forearm, bicep and hand form a:
Class 3 lever
If a ramp that is 3m long is used to reach a loading dock that is 1.5m high, how much work effort force will be expected to push a crate that has a load force of 1200N onto the loading dock?
600N
In a lever, what is the most noticeable difference when you move the fulcrum closer to the load:
Work becomes easier
Force is measured using Newtons. How do you convert kilograms to Newtons
Option 3
The oars on a row boat are an example of a class 1 lever. Which of the following is another example of a class 1 lever?
Scissors
A child pulls a sled up a snow-covered hill. In the process, the child does 405 J of work on the sled. If she walks a distance of 15 m up the hill, how large a force does she exert on the sled?
27N
In class 1 and 2 levers, shifting the fulcrum further from the load makes it ________________ to lift the load.
Harder
Which of the following could be the mechanical advantage of a class 3 lever? What is the effect on work when Mechanical Advantage is greater than one:
work is easier
Two people use a ramp to move a heavy crate onto a truck. If it requires 525N of effort to move the crate, and the ramp is 3m long and reaches a height of 1m. What was the load force is required to move the crate?
1575 N
If someone pulled on the rope in this pulley system with a force of 130 N, which of the following is the greatest load could they lift?
650N
When using the pulley system, the load was raised 2m off of the ground. How far did they need to pull on the free end of the rope?
10m
What is Mechanical Advantage
Mechanical advantage (MA) compares the force that is produced by a machine (the load) with the force that is applied to the machine (the effort force)
MA indicates how much a machine can increase or decrease the force on a load, compared with the effort force.