An object on an inclined plane, the motion of an object on an inclined plane

Solution: Friction f=un= direction oblique downward.

The component of the object's gravity that goes down the inclined plane: mgsin37=6n oblique downward.

The external force of the object f1=f-f-mgsin37=the acceleration of the object a1=f m=2m s2

The velocity of the object after 2s v1=at=4m s

The first process ends, and the second process is brought to the end of the rope break.

f=The force disappears when the rope is broken, and the combined external force of the object is f2=mgsin37+f=accelerationa2=, and the direction is oblique downward.

The object moves in a uniform deceleration motion with initial velocity v1=4m s, and the velocity of elapsed time t2 is 0.

v1=a2t2=

t2 = In the third process, the object slides down at a uniform acceleration on the inclined plane.

Subjected to the combined external force f3 = mgsin37-umgcos37 = acceleration a3 =

Elapsed time t3 reaches velocity vt=22m s=

t3=5s.

Therefore, the speed of the rope reaches 22m s after breaking, and the time is t=t2+t3=

The force is upward along the inclined plane, but it is still at a constant velocity, so there is friction, and this frictional force has an upward component for the inclined plane, so the supporting force will be less than the sum of the gravitational force of the object and the inclined plane.

Inclined planes have a wide range of applications in life, such as winding roads, handling rollers, inclined conveyor belts, etc. The greater the inclination angle between the inclined plane and the plane, and the shorter the inclined plane, the smaller the effort saving, but the distance saving. An inclined plane can lift an object from a low to a high place with relatively little force, but the length of the path to lift the object will also increase.

The bevel is one of the six simple machines proposed by the ancient Greeks. If the slope of the inclined plane is smaller, that is, the angle between the inclined plane and the horizontal plane is smaller, the force to be exerted on the object will be smaller, but the longer the distance will be moved. Vice versa. Assuming that moving the load does not cause energy to be stored or dissipated, the mechanical benefit of the inclined plane is the ratio of its length to the lifting height.

Examples of bevels in real life:

winding mountain road; screw jacks;

Wooden planks are used to build a ramp to push goods onto the car car;

Nanpu Bridge; wood screws;

Blade; Wait a minute.

As long as it's leaning to one place, it's all!

According to the district's teaching recommendations, this lesson is a separate lesson.

1. Teaching Objectives.

1.Know that different objects move differently on an inclined plane.

2.Knowing the shape of an object has something to do with its motion on an inclined plane.

Second, the teaching process.

1.Start with the slide that students are familiar with to arouse their interest in learning! Show the slope** again and have the students observe and name their characteristics (one end is high, the other end is low).

Summarize the concept of inclined planes and ask students to circle the inclined planes in the title in the book to deepen their impression.

2.Demo experiments.

1) Demonstrate a relatively low inclined plane, demonstrate on the podium, in order to facilitate children's observation, you can then demonstrate the object with dark chalk to draw some marks on the object, and tell the students while drawing, put the colored place next to the wooden board, so that the children can observe more easily distinguish whether the object is sliding or rolling.

There are 4 objects demonstrated, a small ball, a small cube, a hexagonal prism and a cylinder.

Results: On the lower inclined plane, the ball and cylinder roll, and the small cube and hexagonal prism do not move.

2) Demonstration on a higher inclined plane, the results of the experiment are: the ball and the cylinder roll, the small cube and the hexagonal prism become sliding. There are also some children who observe very carefully, in addition to the flat side of the hexagonal prism directly on the inclined plane, you can also put the edged side on the inclined plane, the two are different ways, and the form of movement is also different.

Summary: Show the objects you just experimented with and ask the children if they move the same on the inclined plane. They all know it's different. The shape of an object has something to do with how it moves on an inclined plane. Depending on the height of the inclined plane, the motion of the object may also be different.

3.Students use what they have, build their own inclined planes, and experience the movement of different objects on the inclined planes.

Summary. To solve this problem, we can take the following placement method:1

First of all, the center of gravity of the object is determined and the center of gravity is placed at the lowest point of the inclined plane to ensure the stability of the object. 2.Secondly, the support point of the object should be determined and the support point should be placed at the highest point of the inclined plane to ensure the stability of the object.

3.Finally, the support surface of the object is determined and placed at the widest point of the inclined plane to ensure the stability of the object. In order to make the object stable, it is necessary to determine the center of gravity, support point and support surface of the object, and place them at the lowest, highest and widest points of the inclined plane to ensure the stability of the object.

To solve this problem, we can take the following placement method:1First of all, the center of gravity of the object is determined and the center of gravity is placed at the lowest point of the inclined plane to ensure the stability of the object.

2.Secondly, the support point of the object should be determined, and the support point should be placed at the highest mode line point of the inclined plane to ensure the stability of the object. 3.

Finally, the support surface of the object is determined and placed at the widest stool point of the inclined plane to ensure the stability of the object. In order to make the object stable placed, it is necessary to determine the center of gravity, support point and support surface of the object, and place them at the lowest point, highest point and widest point of the incline to ensure the stability of the object.

Fellow, I really didn't understand, I can be more specific.

For the problem of placing objects on inclined planes, there are the following solutions:1Place the object on an inclined plane and hold it in place with a support (such as sticks, stones, etc.) to prevent the object from slipping.

2.Place the object on an inclined surface and secure it with a rope or other similar material to prevent the object from slipping. 3.

Place the object on an inclined surface and hold it in place with a support (such as sticks, stones, etc.) and a soft material underneath the object to reduce sliding. 4.Place the object on an inclined surface and secure it with a rope or other similar material, and pad a soft material underneath the object to reduce slippage.

In addition, when placing objects, you should also pay attention to the slope of the bevel to ensure the safety of the object. If the slope is too large, consider using a support to hold it in place to prevent the object from slipping. In addition, attention should be paid to the weight of the object to ensure the stability of the support.

In short, when placing an object on an inclined plane, attention should be paid to the slope, weight, and use of supports to ensure the safety of the object.

1. Winding mountain road.

The winding mountain road is a common type of mountain road, and its main characteristics are that it is built around the mountain and relying on the hillside, with steep slopes and sharp bends and undulating slopes. The winding mountain road reduces the road slope and enables vehicles to climb the slope by circling around the mountain through the shakumori line;

In the era when bridge and tunnel technology was not developed, winding mountains and paving roads was a helpless choice to cross mountains and mountains. With the rapid development of human economy and technology, more and more highways cross valleys and ridges by erecting bridges and digging tunnels.

2. Approach bridge. When building a bridge over the water, in order to allow large ships to pass smoothly under the bridge, there must be enough clearance under the bridge hole, so that the bridge must be made higher. When the bridge is built higher, the slope between the bridge and the two banks will increase, which will seriously affect the traffic between the upper and lower bridge decks.

The approach bridge is the "transition" between the bridge and the road, gradually raising or lowering the road surface so that vehicles can smoothly go up and down the bridge deck.

3. Tile house. The roof slope of the tiled house in the north is moderate, generally not more than 45 degrees; Due to the heavy rain in the south, the slope is larger than that in the north.

The tile house is a traditional Chinese residential building, which embodies a kind of elegant, simple and quiet beauty, and is also the carrier of traditional Chinese culture. Nowadays, more and more old buildings have disappeared, and the former culture and beauty can only be traced in the **.

4. Slides. Slides are a kind of rotten children's sports equipment, commonly found in kindergartens or children's playgrounds, suitable for children aged 3-6 years old, and there are also slides for special purposes, such as slides used for life-saving. The slide is equipped with a ladder on one side of the high shelf, and an inclined skateboard (generally there are two types) on the other side, and children go up from the ladder and slide down the slope.

5. Screws. Screws are tools that use the physical and mathematical principles of the oblique circular rotation and friction of objects to tighten the artifacts step by step. Screws are a generic term for fasteners, everyday colloquialism.

1) From δs=at2, there is x bc-x ab=at 2, x ab-x oa=at 2, and the sign of despair is x bc-x ab=x ab-x oa, that is, 15cm-10cm=10cm-x oa, x oa=5cm. and a=

2) vb = (x ab + x bc) 2t = and lease s

3) By vb=at, so t=vb ruler celebrates a=, so there are two balls on the b ball, and there is only one ball on the a ball.

Analysis: 1. According to the symmetry of the rising and descending motion process on the smooth inclined plane, it can be seen that the uniform acceleration linear motion with zero muzzle velocity from the highest point to the lowest point is t1=2s to point b, and the time taken to point A is t2=4s, so there are: ab=1 2at2 -1 2at1 =6m

Solution: a=1m s

So the distance from the highest point to a is: x=1 2at2 = 1 2*1*4 m=8m

2. The velocity when passing through point A is: va=at2=4m s, and the velocity when passing through point b is: vb=at1=2m s