Позабыл topic simple machines. Методическая разработка занятия по английскому языку на тему "Машины и работа" (3 курс)
Topic 9
Simple Machines
A screwdriver is used to pry the lid off a can of paint. What type of lever is the screwdriver in this instance?
1st Class Lever
2nd Class Lever
3rd Class Lever
It’s actually acting as an inclined plane.
10
12
3.0
8.3
25
75
10
29
1.7
3.5
28
350
10
Participant Scores
12
Jacob
Joey
Daniel
David
Nicole B.
A single pulley is used to hoist a safe with a mass of 45. 0 kg
A single pulley is used to hoist a safe with a mass of 45.0 kg. If the machine is 100% efficient, what effort force will be required to hoist the safe?
45.0 N
90.0 N
205 N
266 N
441 N
10
A snow shovel is an example of which type of lever? (Hint: The handle of the shovel is the fulcrum.)
1st Class
2nd Class
3rd Class
10
How long must an inclined plane be to push a 100 kg object to a height of 2.0 meters using a force of 200 N? Friction can be ignored.
2.0 m
9.8 m
50 m
100 m
200 m
400 m
10
A wheel and axle machine requires an effort force of 5.0 N to lift a load with a mass of 5.1 kg. If the machine is ideal and has a wheel radius of 12 cm, what is the radius of the axle?
1.0 cm
1.2 cm
5.0 cm
10 cm
1.2 m
2.4 m
10
Participant Scores
28
Jacob
Joey
Daniel
David
Mackenzie
20 N
25 N
196 N
245 N
1960 N
Answer Now
10
What force will be required to push a 500 N box to a height of 2.50 meters on a ramp that is 10.0 meters long and 85% efficient?
4.00 N
50.0 N
106
125 N
147 N
10
1
2
3
4
5
10
0.50
1.00
1.50
2.00
2.50
Answer Now
10
Participant Scores
44
Jacob
Mackenzie
39
Nicole F.
Joey
Daniel
A ramp is 12 meters long and 3.0 meters high. It takes 145 N of force to push a 400 N crate up the ramp. Determine the efficiency of the ramp.
.36 %
.69 %
3.0 %
8.2 %
36 %
69 %
145 %
10
An object is placed 1. 75 meters from the fulcrum of a lever
An object is placed 1.75 meters from the fulcrum of a lever. The effort force is 0.50 meters from the fulcrum. What is the actual mechanical advantage if the lever is 95% efficient?
.271
.286
.301
3.33
3.50
3.68
Answer Now
10
20%
31%
69%
80%
87%
96%
Answer Now
10
Participant Scores
56
Jacob
Mackenzie
51
Nicole F.
Joey
Daniel
A certain ramp is 10 meters long and is 50% efficient
A certain ramp is 10 meters long and is 50% efficient. It requires 25 N of force to push a 50 N crate up the ramp. How tall is the ramp?
1.0 m
2.0 m
2.5 m
3.5 m
4.0 m
5.0 m
22
Participant 1
Participant 2
Participant 3
Participant 4
Participant 5
Participant 6
Participant 7
Participant 8
Participant 9
Participant 10
Simple machines are extremely important to everyday life. They make stuff that is normally difficult a piece of cake. There are several types of simple machines. The first simple machine is a lever. A lever consists of a fulcrum, load, and effort force. A fulcrum is the support. The placing of the fulcrum changes the amount of force and distance it will take in order to move an object. The load is the applied force. The effort force is the force applied on the opposite side of the load.
Levers can be placed in three classes. The 1st class levers are objects like pliers where the fulcrum is at the center of the lever. The 2nd class of levers are objects that have the fulcrum on the opposite side of the applied force like a nutcracker. The 3rd and final class is objects like crab claws. These objects of the load at one end and the fulcrum on the other.
An inclined plane is another simple machine.
Inclined planes are also known as ramps. Ramps make a trade off between distance and force. No matter how steep the ramp, the work is still the same. A winding road on a mountain side is a good example of a ramp. Some simple machines are modified inclined planes. The wedge is one of those machines. One or two inclined planes make up a wedge. Saws, knives,needles, and axes are made from wedges. The screw is another modified inclined plane. Screws decrease the force but increase the distance. The ridges are called threads. A couple of simple machines are made with wheels. The wheel and axle is one of these machines.
These are made with a rod joined to the center of a wheel. They can either increase distance or force, depending on the size of the wheel. The pulley is another machine that uses wheels. The are a wheel with a groove in the center with a rope or chain stretched around it. The load attaches to one end and the effort is applied to the other on all pulleys. There are two types of pulleys. The fixed pulley stays in one place while the wheel spins. Movable pulleys attach to objects. Several pulleys can be used at one time. A good example of a pulley system is an escalator. Simple machines make up compound machines. We use these machines daily. Life would be difficult without simple machines.
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Simple Machines. (2016, Dec 12). Retrieved from ">APA "Simple Machines." StudyMoose , 12 Dec 2016, ">MLA StudyMoose. (2016). Simple Machines . . Available at: ">Harvard "Simple Machines." StudyMoose, Dec 12, 2016. Accessed January 17, 2020.
Of course, depending on the gun. Some are a lot more simple than others. All are “simply” machines, but not all are “Simple” machines.
A matchlock, from the 1600’s was simple, very simple, and a modern electric gatling gun, not so simple.
Col. Colt literally went broke because his first revolver, the Paterson Colt was not simple enough.
He built a large supply of revolving guns, on credit, then tried to sell them to the U.S. Army, who rejected the gun as being too fragile and too complex for use in the field.
The existing muzzle-loading pistols only had 3 moving parts, all simple to get to and to repair.
The Paterson had no trigger guard. Rather, the trigger was recessed in the frame, and when the hammer was cocked, the trigger was pushed out where it could be squeezed.
Also you had a revolving cylinder, and linkage with the hammer to move the cylinder and to index the next chamber with the barrel.
And there was added linkage from the hammer, to push the trigger out into firing position and retract it afterwards.
It had well over double the number of moving parts of a single-shot, requiring more parts inventory in the field, and repairs only by a skilled armorer, when something quit working, plus possibility of powder fouling or mud jamming the cylinder. A very few initial guns were bought as a trial, then the design was rejected completely.
So, he couldn’t sell his guns to the U.S. Army, and worse than THAT, they acquired a stink that kept them from selling in the civilian market.
Since they weren’t good enough for the Army, why would anyone else want one?
That was until The Republic Of Texas came along.
Until that time, Colt Patent Firearms was nearly done for… they were already entering bankruptcy proceedings. `
Texas put in a large order, pretty much emptying that warehouse full of guns that nobody wanted except Sam Colt’s creditors.
The first thing was that the immediate money from that order saved Colt from bankruptcy by the skin of his teeth.
The next, more important thing was that The Texas Army, Texas Navy, and (especially) The Texas Rangers used them, which created the civilian market that the U.S. Army had destroyed for him.
In The Battle Of The Bay Of Campeche, the Texas Navy defeated the Mexican Navy, and as a nod to The Republic Of Texas, Colt produced the model 1851 Navy with an engraved cylinder standard, depicting this naval battle.
In addition, to creating a market, the Rangers found a few design flaws, so Captain John Coffee Hays and Capt. Samuel Walker (The Walker Colt ) went to Connecticut with plans for design changes.
The result was The Colt Patterson #5 Holster model, marketed by Colt as “The Texas Paterson”.
The original concept was that the Paterson was an infantry weapon. When you fired your five shots, you could lay flat on the ground, partially disassemble it for reloading, then re-assemble and go on fighting.
The most important use of Colt Revolvers was by The Texas Rangers, who often had to fight Indians on horseback.
To reload the gun, you had to remove the barrel wedge, then remove the barrel, then stuff powder and ball into each chamber with a special supplied tool, then follow those steps in reverse.
If the cylinder, barrel, or barrel wedge fell out of your hands, the gun was useless.
Most Rangers got around that by wearing a sash around their waist and sticking loose parts in there while they just switched in a spare loaded cylinder.
That was in addition to carrying two revolvers, so they had a better chance of getting through an encounter without having to actually stuff powder and balls into the chambers to reload.
So the two most major changes the went to Sam Colt with was to increase caliber from .28 to .36 and produce a different shape on the grip.
Then two years later, Captain Hayes campaigned for the addition of a loading lever, and a capping port in the rear, so no disassembly was required to reload on the back of a galloping horse. Colt made the change to the Texas Paterson.
The Comanche sometimes wore breastplates made of 18-inch lengths of reeds packed in dried mud, and this would often stop a light little .28 caliber ball.
Captain John Coffee Hayes (Called “Devil Jack” by local Indians) first introduced The Comanche to Colt Patent Firearms at The Battle Of Enchanted Rock , in 1841.
He was a surveyor by trade, and climbed to the top of the highest feature in the area, (Enchanted Rock) to have a good look at the lay of the land.
Unfortunately, Enchanted Rock was sacred to both the Comanche and Tonkawa tribes, who believed that evil spirits lived there and are rumored to have made human sacrifices at the base of the rock to keep from getting on the bad side of the spirits. The Comanches caught him alone up there.
In a 3-hour solo battle, he killed them until they took refuge in caves at the base of the rock.
How many of them he killed, before they hid from him, depends on whom you ask, but the lowest count is 15.
Enchanted Rock was already believed by them to be home to evil spirits, and they became convinced that those spirits were on the side of Hays, or that he was actually one OF them.
He had two Texas Patersons, a rifle and a Bowie Knife with him.
Standard Indian tactic was to goad a Ranger into shooting OR shooting AT three of them in quick succession, then charging in for a kill before any reloading of his two pistols and a rifle could happen.
That’s how it worked with two single-shot pistols and a single-shot rifle.
Enchanted Rock was their first exposure to someone who could fire 11 shots without reloading.
At one point, he killed a couple of them climbing up after him with his Bowie Knife, another piece of standard equipment for Rangers.
What do a bicycle and a car have in common? They both move using the simple machine wheel and axle. In this lesson, students learn about how this simple machine works, and will identify objects that use a wheel and axle.
Download lesson planMaterials and preparation
Related books and/or media
Key terms
- simple machine
- wheel
Learning Objectives
Students will be able to explain how the wheel and axle work as a simple machine. Students will be able to identify objects which use the wheel and axle.
Explicit Instruction/Teacher modeling
(15 minutes)- Distribute small toy cars that have wheels joined by axles to groups of students. Kick-start a discussion with some questions about the toy car mechanics, such as: How do these toy cars move? How are the wheels on each side of the car joined to each other?
- Have a student volunteer point to the rod that holds the two wheels together. Explain that the bar that joins two wheels is called an axle .
- Tell students that they will be learning about wheels and axles.
- Hold up the doorknob, explaining that it is an everyday example of a wheel and axle.
- Challenge the students to help you identify the wheel and axle in the doorknob. Listen as different students call out their guesses.
- After some speculation, tell students that the knob that turns is the wheel. The inner rod that is attached to the knob is the axle.
- Demonstrate how the wheel and axle works by turning the knob (wheel). That turns the inner rod (axle) and moves the latch, to open the door.
Guided Practice
(15 minutes)- To consolidate student thinking, set up activity stations with play dough and a rolling pin.
- Let students practice flattening the dough with the pin.
- Guide them to express these understandings: The rolling pin is a wheel and axle. When you push on the handles (the axle) the wheel turns and flattens out the dough.
- Challenge students to think of other common machines that have one wheel like the rolling pin. Great examples include a wheelbarrow, a top, and a playground merry-go-round.
Independent working time
(15 minutes)- Pass out a copy of the Wheel and Axle worksheet to each student to complete independently.
- Walk around the classroom to offer support to students who get stuck.
Differentiation
- Enrichment: Have students who need more of a challenge read a history of other simple machines, and fill out an accompanying word search.
- Support: Put students who need more support into pairs to complete the Wheel and Axle worksheet.
Assessment
(10 minutes)- Collect the worksheets that the students have filled out, and correct them using the Wheel and Axle answer sheet.
Review and closing
(5 minutes)- In summary, remind students that the rolling pin is a wheel and axle. When you push on the handles (the axle) the wheel turns and flattens out the dough.
- Challenge students to think of other common machines that have one wheel like the rolling pin, such as a wheelbarrow, top, and merry-go-round.
- Remind your class that the wheel and axle is only one of six common simple machines that help things move. For homework or additional independent work, consider encouraging students to learn more about other kinds of simple machines.