Science Chapter 5 - Review Flashcards
What are six simple machines
There are six different machines - The lever, wheel and axle, pulley, inclined plane, screw, wedge
What is a lever
A lever is a rigid bar that is supported at one point. This point is called the fulcrum
What are the three classes of levers
There are three different types…
A first class lever is a lever with the fulcrum located between both input and output forces. An example could be a prybar
A second class lever is a lever where the fulcrum is located at the end of the bar. An example of this is a bottle cap opener
A third class lever is a lever where the fulcrum is located where we place our hand. Our hand becomes the fulcrum. An example of this is a rake.
How do we calculate the IMA of a lever
We calculate the IMA of a lever by dividing the length of the input arm by the length of the output arm…
IMA = Lin / Lout
What is a pulley, How do we calculate the IMA of a pulley
A pulley consists of a grooved wheel with a rope or cable looped around it. A pulley is only able to change the direction of a force or increase the output force. You can find two types of pulleys, Fixed or moveable.
The IMA of a pulley is calculated by counting the support ropes in the pulley system
What is a wheel and axle
A wheel and axle consist of a shaft or axle that is attached to a larger disk, called the wheel. An example is a screwdriver
How do we calculate the IMA of a wheel and axle
There are two different ways to calculate the IMA of a wheel and axle. The way we use depends on where the input force is being applied.
If the force is being applied at the wheel we use the formula
IMA = rw / ra
If the force is being applied at the axle we use the formula
IMA = ra / rw
What is a inclined plane
A sloping surface on which and object can move is called an inclined plane or ramp. A ramp reduces the forces needed to push and object upward but increases the distance needed to push that object
How do we calculate the IMA of a inclined plane
We calculated the IMA of a ramp by dividing the length of a ramp by the height of the ramp
IMA = L / H
What is a Screw, How do we calculate the IMA of a screw
A Screw is simply a inclined plane wrapped around a rod. This inclined plane on a screw is called a thread. We calculate the IMA of the Screw the same way we calculate the IMA of an inclined plane
What is a wedge, How do we calculate the IMA of the wedge
A wedge is a inclined plane, but it is used to pierce through objects and materials instead of a ramp being used to push things up and down it. We calculate the IMA of the wedge the same way we calculate the IMA of an inclined plane
What is a Mechanism
A mechanism consists of several or more simple machines. At the very least it contains more than two. These simple machines are all working together to preform a task
What is the Perpetual Motion Machine
A perpetual Motion Machine, is a machine that is able to produce 100% Efficiency. To have this machine reach 100% efficiency, It would need to break the laws of physics by not having any friction on it.
What is Efficiency of machines
The Efficiency of a machine measures the useful work done by the machine compared to the work needed to operate it. Useful output work is the work that the machine is designed to preform.
What does friction do to machines
Friction plays a large factor into efficiency as friction is a large factor into why machines never reach 100% efficiency. Whenever parts of a machine move, parts of there energy is taken by friction. For example, when the wheel rotates on the shaft of they pulley, an amount of energy is transformed into heat energy due to friction. Because of this factor, we need to put in more input work to compensate for the loss of energy.
