Formula
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What is the formula for work?
Work = Distance X Force
What is a simple machine?
A simple machine uses few or no moving parts to make work easier.
A construction worker uses a pulley system to lift a block. What is one of the purposes of the pulley system?
To change the direction of the force needed to move the block.
Describe the relationship between work and force.
The displacement of an object due to the application of force is work.
A longer ramp will result in less force being used over a longer distance.
True or False?
True
What is the unit of force?
Newtons
How is fulcrum defined?
The point where a level pivots.
In order to calculate the force exerted to perform work, which formula should be used?
force = work/distance
What advantage does a set of stairs have over a ladder that goes straight up?
The total amount of force is less, although the distance traveled is greater.
How is a pulley helpful for lifting objects?
It allows objects to be lifted with less force and applied in a downward direction.
What is the unit of work?
Force
What is mechanical force?
The amount of energy used to move an object.
Which car has the highest efficiency? (Assume all cars have the same mass.)
20km on 2 liters of gas
20km on 1 liter of gas
25 km on 2 liters of gas
25 km on 1 liter of gas
2k km on 1 liter of gas
How do you calculate the work done on an object when you push it?
You multiply the force you apply by the distance over which you are pushing.
How does using an inclined plane change the work for some students moving boxes?
The inclined plane reduced the amount of force required to do work on the box.
A bowling ball has a mass of 6 kilograms. A person lifes the bowling ball 2 meters above the ground, using a force of about 60 newtons. How much work did the person do?
120 joules
What is the relationship between simple machines, a lever, a fulcrum, effort and load?
A lever is a type of simple machine made of a bar that pivots on a fixed point called a fulcrum, which reduces effort needed while producing more work to move a load.
The efficiency of a machine can be increased by reducing the input energy and increasing the output energy.
True or False.
(Picture your examples)
True
Why can a machine not reach 100% efficiency in the real world?
Machines must overcome forces of friction.
How are levers classified?
Levers are classified according to the position of the effort, load, and fulcrum.
Find the order of each for all three Levers
How much work is done if u kick a weighted ball and it doesn't move, but you break a toe?
No work.
What is the distance between the starting point of an object and its ending point is called?
Displacement
Explain how a lever that magnifies force can be beneficial.
A lever that magnifies force allows a person to produce more work with less effort.
By using a pulley system, a farmer makes it easier to lift bales of hay by reducing the force needed. The energy she uses to complete the task is 10,000 joules, and the work done on the bales of hay is 8,000 joules. What was her efficiency in this task?
80%
(output energy / input energy) X 100
An inclined road on a hill could be used as a simple machine.
True or False.
True