Mechanical Advantage and Efficiency. Mechanical Advantage Machines can take a small input force and...
-
Upload
godwin-gregory -
Category
Documents
-
view
219 -
download
2
Transcript of Mechanical Advantage and Efficiency. Mechanical Advantage Machines can take a small input force and...
![Page 1: Mechanical Advantage and Efficiency. Mechanical Advantage Machines can take a small input force and create a large output force. The mechanical advantage.](https://reader035.fdocuments.in/reader035/viewer/2022071714/56649e0f5503460f94af96fa/html5/thumbnails/1.jpg)
Mechanical Advantage and Efficiency
![Page 2: Mechanical Advantage and Efficiency. Mechanical Advantage Machines can take a small input force and create a large output force. The mechanical advantage.](https://reader035.fdocuments.in/reader035/viewer/2022071714/56649e0f5503460f94af96fa/html5/thumbnails/2.jpg)
Mechanical Advantage
Machines can take a small input force and create a large output force.
The mechanical advantage of a machine is the number of times that the machine increases an input force.
There are two ways to calculate the mechanical advantage of a machine: actual and ideal.
![Page 3: Mechanical Advantage and Efficiency. Mechanical Advantage Machines can take a small input force and create a large output force. The mechanical advantage.](https://reader035.fdocuments.in/reader035/viewer/2022071714/56649e0f5503460f94af96fa/html5/thumbnails/3.jpg)
Actual Mechanical Advantage
The actual mechanical advantage (AMA) equals the ratio of the output force to the input force.
AMA = Output Force / Input Force
![Page 4: Mechanical Advantage and Efficiency. Mechanical Advantage Machines can take a small input force and create a large output force. The mechanical advantage.](https://reader035.fdocuments.in/reader035/viewer/2022071714/56649e0f5503460f94af96fa/html5/thumbnails/4.jpg)
Mechanical Advantage Problems
Q: Alex pulls on the handle of a claw hammer with a force of 15 N. If the hammer has a actual mechanical advantage of 5.2, how much force is exerted on a nail in the claw?
Q: If you exert 100 N on a jack to lift a 10,000 N car, what would be the jack’s actual mechanical advantage (AMA)
A: output force = (5.2)(15N) = 78 N
A: AMA= 10,000 N / 100 N = 100
![Page 5: Mechanical Advantage and Efficiency. Mechanical Advantage Machines can take a small input force and create a large output force. The mechanical advantage.](https://reader035.fdocuments.in/reader035/viewer/2022071714/56649e0f5503460f94af96fa/html5/thumbnails/5.jpg)
Ideal Mechanical Advantage
The ideal mechanical advantage (IMA) is the maximum mechanical advantage a machine can have.
To have the maximum mechanical advantage, there must be no friction.
IMA = Input distance / Output distance
![Page 6: Mechanical Advantage and Efficiency. Mechanical Advantage Machines can take a small input force and create a large output force. The mechanical advantage.](https://reader035.fdocuments.in/reader035/viewer/2022071714/56649e0f5503460f94af96fa/html5/thumbnails/6.jpg)
Mechanical Advantage Problems
Q: Calculate the ideal mechanical advantage (IMA) of a ramp that is 6.0 m long and 1.5 m high?
Q: The IMA of a simple machine is 2.5. If the output distance of the machine is 1.0 m, what is the input distance?
A: IMA = 6.0m / 1.5m = 4.0
A: Input distance = (2.5)(1.0m) = 2.5 m
![Page 7: Mechanical Advantage and Efficiency. Mechanical Advantage Machines can take a small input force and create a large output force. The mechanical advantage.](https://reader035.fdocuments.in/reader035/viewer/2022071714/56649e0f5503460f94af96fa/html5/thumbnails/7.jpg)
AMA vs IMA
AMA is what actually happens
IMA is what could happen without friction
Since there is always some friction, AMA is less than IMA.
![Page 8: Mechanical Advantage and Efficiency. Mechanical Advantage Machines can take a small input force and create a large output force. The mechanical advantage.](https://reader035.fdocuments.in/reader035/viewer/2022071714/56649e0f5503460f94af96fa/html5/thumbnails/8.jpg)
EfficiencyWe always want to see how efficient a
machine is.
Most cars get at least 20 miles per gallon. This is an example of efficiency.
We say that a car that gets 30 miles per gallon is more efficient.
With efficiency, we compare how much work we get from the work we put into a machine.
![Page 9: Mechanical Advantage and Efficiency. Mechanical Advantage Machines can take a small input force and create a large output force. The mechanical advantage.](https://reader035.fdocuments.in/reader035/viewer/2022071714/56649e0f5503460f94af96fa/html5/thumbnails/9.jpg)
Efficiency
Efficiency =
(Work output / Work input) X 100%
Because there is always some friction, the efficiency of any machine is always less than 100 percent.
![Page 10: Mechanical Advantage and Efficiency. Mechanical Advantage Machines can take a small input force and create a large output force. The mechanical advantage.](https://reader035.fdocuments.in/reader035/viewer/2022071714/56649e0f5503460f94af96fa/html5/thumbnails/10.jpg)
Efficiency ProblemsQ: Alice and Jim calculate that they must do 1800 J of
work to push a piano up a ramp. However, because they must also overcome friction, they must actually do 2400 J of work. What is the efficiency of the ramp?
Q: If the machine has an efficiency of 40%, and you do 1000 J of work on the machine, what will be the work output of the machine?
A: 1800 J/ 2400 J x 100 = 75%
A: Work Output = (Efficiency x work input) / 100% Work Output = (40% x 1000 J) / 100% = 400J