Independent work on physics Newton's first law. Independent work

CHECK PAPER No. 2 on the topic: “Newton’s Laws”

Purpose of the work: identifying students’ mastery of the mandatory minimum knowledge and skills:

Knowledge of basic concepts and quantities: - vector recording of Newton's laws, as well as finding projections of force and acceleration vectors; - physical laws: Newton's first, second and third laws.

INSTRUCTIONS

Date: December

The work contains 3 tasks with a detailed solution, in 2 versions. In each option the tasks are equivalent. 45 minutes are allotted for completion.

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CHECK PAPER No. 2 on the topic: “Newton’s Laws”

9th grade.

Purpose of the work : identifying students’ mastery of the mandatory minimum knowledge and skills:

Knowledge of basic concepts and quantities: - vector recording of Newton's laws, as well as finding projections of force and acceleration vectors; - physical laws: Newton's first, second and third laws.

INSTRUCTIONS

Date: December

The work contains 3 tasks with a detailed solution, in 2 versions. In each option the tasks are equivalent. 45 minutes are allotted for completion.

Test text

OPTION 1

1. With what acceleration did a jet aircraft weighing 50 tons move during takeoff, if the engine thrust force is 80 kN?

2. What is the force that imparts an acceleration of 0.4 m/s to a body weighing 3 kg? 2 ?

3. A skier weighing 60 kg, having a speed of 36 km/h at the end of the descent, stopped 40 s after the end of the descent. Determine the force of resistance to its movement.

OPTION 2

1. A trolley weighing 200 kg moves with an acceleration of 0.2 m/s 2 . Determine the force imparting this acceleration to the trolley.

2. What is the acceleration with which a body of mass 3 kg moves if a force of 12 N acts on it?

3. An empty truck weighing 3 tons began to move with an acceleration of 0.2 m/s 2 . What is the mass of this car together with the load if, with the same traction force, it moves away with an acceleration of 0.15 m/s 2 ?

Instructions for checking the problem solving task

The solution to each problem is assessed in points (see table), and for certain errors the number of points is reduced.

EVALUATION CRITERIA:

“3” - any two tasks were solved correctly;

“4” - all tasks were solved, but one mistake or two shortcomings were made;

“5” - all tasks were solved correctly.

Solution of option I

Independent work on physics Newton's laws, grade 10 with answers. There are 5 options for independent work. Each option has 2 tasks.

1 option

1. A ball of mass 1 kg moves with an acceleration of 50 cm/s 2 . Determine the force acting on the ball.

2. A body of mass 5 kg is subject to forces of 3 N and 4 N, directed to the south and west, respectively. What is the acceleration of the body and where is it directed?

Option 2

1. A force of 2 mN acts on a body of mass 5 g. Find the acceleration with which the body moves.

2. A sled with a mass m = 10 kg moves east with an acceleration a = 0.5 m/s 2 under the influence of two forces, one of which F 1 = 20 N is directed to the west. Where is the direction and what is the force F 2 acting on the sled?

Option 3

1. A body weighing 4 kg under the influence of some force acquires an acceleration of 2 m/s 2 . What acceleration will a body of mass 10 kg acquire under the influence of the same force?

2. A load moving vertically upward with an acceleration a = 2 m/s 2 is acted upon by two forces: F1 = 8 N, directed vertically upward, and F2 = 3 N, directed vertically downward. What is the mass of the cargo?

Option 4

1. Determine the mass of the body to which a force of 50 mN imparts an acceleration of 0.2 m/s 2 .

2. A block of mass m = 200 g is acted upon by two forces: a force F 1 = 1 N, directed to the south, and a force F 2 = 1.5 N, directed to the north. With what acceleration is the block moving?

Option 5

1. A force of 60 N imparts an acceleration of 0.8 m/s 2 to the ball. What force will give this ball an acceleration of 2 m/s 2?

2. The car moves with acceleration a = 2 m/s 2 under the influence of two forces: engine traction force F 1 = 10 kN and resistance force F 2 = 4 kN. Force F 1 is directed to the south, force F 2 is opposite to the direction of movement of the car. What is the mass of the car?

Answers to independent work in physics Newton's Laws, grade 10
1 option
1. 0.5 N
2. 1 m/s 2, to the southwest
Option 2
1. 0.4 m/s 2
2. to the east, 25 N
Option 3
1. 0.8 m/s 2
2. 2.5 kg
Option 4
1. 0.25 kg
2. 2.5 m/s 2
Option 5
1. 150 N
2. 3000 kg

NEWTON'S LAWS

Option1

Entry level

1. The bus moves at a constant speed. Choose the correct statement.

A. The only force acting on the bus is gravity.

B. The resultant of all forces applied to the bus is zero.

B. The acceleration of the bus is constant and different from zero.

2. A body weighing 200 g moves with an acceleration of 0.5 m/s 2 . Choose the correct statement.

A. The resultant of all forces applied to the body is 0.1 N.

B. The resultant of all forces applied to the body is 100 N.

B. The resultant of all forces applied to the body is zero.

3. In which of the following cases are we talking about the movement of bodies by inertia? Choose the correct statement.

A. A man slips and falls backwards.

B. The rider flies over the head of a stumbled horse.

B. An air bubble moves uniformly and in a straight line in a tube with water.

Intermediate level

1. a) Can a car move uniformly on a horizontal highway with the engine turned off?

B) Under the influence of what force does a body weighing 1 kg acquire an acceleration of 1 m/s 2?

Q) How to explain the phenomenon of recoil when fired?

B) What does the acceleration of a body depend on?

C) Give examples showing that the forces resulting from the interaction of two bodies are identical in nature.

Sufficient level

1. a) The ball hangs on a thread. What forces are acting on the ball? Why is he at rest? Represent the forces graphically.

B) What is the mass of a body to which a force of 12 N imparts an acceleration of 3 m/s 2?

C) When a motor ship collides with a boat, it can sink it without causing any damage. How does this agree with the equality of force moduli during interaction?

2. a) A load is suspended from the ceiling of the cabin of a ship moving uniformly and in a straight line. How will the cargo move relative to the cabin if the ship: increases its speed? slow it down? turn left?

B) What acceleration does a force of 8 N impart to a body weighing 300 g?

Q) What can be said about the acceleration that the Earth receives when interacting with a person walking on it? Justify your answer.

Independent work 4

^ NEWTON'S LAWS

Option 2

Entry level

1. The ball moves under the influence of a force that is constant in magnitude and direction. Choose the correct statement.

A. The speed of the ball does not change.

B. The ball moves uniformly.

B. The ball moves with constant acceleration.

2. How does a ball of mass 500 g move under the influence of a force of 4 N? Choose the correct statement.

A. With an acceleration of 2 m/s 2.

B. At a constant speed of 0.125 m/s.

B. With a constant acceleration of 8 m/s 2.

Intermediate level

1. a) Why is Newton’s first law called the law of inertia?

B) How does a body move if the vector sum of the forces acting on it is zero?

B) A mosquito hit the windshield of a moving car. Compare the forces acting on a mosquito and a car during an impact.

2. a) Under what condition can a body move uniformly and rectilinearly?

B) Using two identical balloons, different bodies are lifted from rest. By what criteria can we conclude which of these bodies has the largest mass?

B) The ball hits the window glass. Which body (ball or glass) experiences the greatest force upon impact?

Sufficient level

1. a) There is a block on the table. What forces are acting on it? Why is the block at rest? Represent the forces graphically.

B) With what acceleration does a jet aircraft weighing 60 tons move during takeoff if the thrust force of the engines is 90 kN?

C) When a motor ship collides with a boat, it can sink it without causing any damage. How does this agree with the equality of the moduli of interaction forces?

2. a) In what ways is an ax mounted on a handle? How to explain the phenomena occurring in this case?

B) What force imparts an acceleration of 2 m/s 2 to a body weighing 400 g?

Q) Two boys pull a cord in opposite directions, each with a force of 100 N. Will the cord break if it can withstand a load of 150 N?

Independent work 4

^ NEWTON'S LAWS

Option 3

Entry level

1. The plane flies horizontally in a straight line. The speed of the aircraft increases in direct proportion to time. Choose the correct statement.

A. The plane moves uniformly and in a straight line.

B. The resultant of the forces applied to the plane is non-zero.

B. The resultant of all forces applied to the plane increases with time.

2. Under the influence of a force of 2 N, a body moves with an acceleration of 0.5 m/s 2 . Choose the correct statement.

A. Body weight 1 kg.

B. The body moves at a constant speed.

B. Body weight 4 kg.

3. In which of the following cases are we talking about the movement of bodies by inertia? Choose the correct statement.

A. The body lies on the surface of the table.

B. After turning off the engine, the boat continues to move on the surface of the water. B. A satellite is moving in orbit around the Earth.

Intermediate level

1. a) Can a puck thrown by a hockey player move uniformly across the ice?

B) Under what condition does the body acquire acceleration?

Q) Give examples of the manifestation of Newton's third law?

2. a) Why doesn’t cargo dropped from an airplane fall vertically?

B) Why is falling from a certain height onto frozen ground more dangerous than falling onto loose snow?

C) The book lying on the table presses on him with some force. The table acts on the book with the same force directed upward. Is it possible to find the resultant of these forces?

Sufficient level

1. a) The parachutist descends, moving uniformly and in a straight line. What forces are being compensated? Make a drawing.

B) What force imparts an acceleration of 2 m/s 2 to a body weighing 3 kg?

C) Baron Munchausen claimed that he pulled himself out of the swamp by his hair. Justify the impossibility of this.

2. a) Under what condition will a steamboat sailing against the current have a constant speed?

B) What acceleration does a force of 30 N impart to a body weighing 5 kg?

c) Why does the boat not move when a person in it presses on the side, and starts moving if a person gets out of the boat and pushes it with the same force?

Back Forward

Attention! Slide previews are for informational purposes only and may not represent all the features of the presentation. If you are interested in this work, please download the full version.

Lesson type: A lesson in repeating and summarizing the material studied.

Lesson objectives:

• Repetition, generalization, consolidation and systematization of Newton's laws;
• Testing students' knowledge on the topic "Newton's Laws";
• Formation in students of practical skills and abilities to apply knowledge to solve experimental, computational, and qualitative problems.

Lesson objectives:

Educational:

• Repeat and generalize Newton's laws;
• Strengthen and test skills in solving experimental, computational and qualitative problems;

Educational:

• Develop skills in presenting a complete and correct answer;
• Develop the ability to apply acquired knowledge to solve problems;
• Develop logical thinking;

Educational:

• Foster cognitive interest in the study of physical laws and phenomena;
• To teach to see the manifestations of the studied patterns in the surrounding life;

Required equipment and materials:

• two cylinders connected by a thread,
• tripod with coupling,
• coin with ruler,
• computer with projector, lesson presentation made in PowerPoint,
• interactive board.

Also included with the lesson is booklet .

Lesson progress

1. Organizational stage

Hello guys! I hope that you and I will work fruitfully in class today. And I would like this lesson to be interesting for everyone.

Our lesson is devoted to repetition and generalization of knowledge on the topic: "Newton's Laws". And the epigraph: “Truth is what stands the test of experience” (There is a discussion of the meaning of the words of the epigraph).

Lesson Plan

1. Inertial reference systems. Newton's First Law.
2. What is strength? Newton's Second Law.
3. Newton's Third Law.
4. Forces existing in nature
5. Manifestation of the studied patterns in the surrounding life.
6. Homework

2. Updating basic knowledge

As you can see from the lesson plan, now we will talk about Newton's laws. You remember from the 7th grade physics course that the main sources of physical knowledge are observations and experiments. Therefore, today we will not only solve problems, but also perform experimental tasks and watch episodes from our favorite cartoons. And then let's see whether Newton's laws are actually fulfilled or whether these laws are violated. First, let's remember how they are formulated.

Newton's first law?

Newton's second law?

Newton's third law?

What forces do you know?

How do they act on the body?

But according to Newton's third law, bodies interact, i.e. and the body, in turn, acts on:. What? What forces are we talking about in this case?

3. Consolidation and systematization of knowledge

Now let's move on to discussing the interaction of the Earth and the body. The fact that the Earth attracts all bodies to itself and acts on bodies with a certain force is obvious to us. But can we act on Earth with a certain force? We do not see the manifestation of this force, but this does not mean at all that it does not exist.

Slide No. 9

1) There is a discussion of the interaction of the Earth and the body.

A man is standing on a chair. A force of, say, 600 N acts on him from the Earth. According to Newton’s Third Law, a force of 600 N also acts on the Earth from a person. Why doesn’t the Earth fall on a person?

From a theoretical point of view:

According to Newton's third law: F 1 = F 2;

According to Newton's second law: m 1 a 1= m 2 a 2;

Conclusion: the greater the mass, the less the acceleration of the body, i.e. changing its speed.

2) Experimental task No. 1

This conclusion is evaluated empirically. On the table is a tripod with a coupling and a foot, two connected cylinders. The interaction of these cylinders is being observed and the students are faced with the task: to track at what angle each cylinder will deviate after the interaction, compare these angles and compare the masses of the cylinders, weighing them on scales. The experiment is carried out at least three times.

So what results did you get? (bodies of equal mass - the angles are equal; the greater the mass, the smaller the angle of deflection, although the interaction time is the same).

So, as a result of interaction, the cylinders acquired different velocities in magnitude, and, consequently, different acceleration magnitudes: a cylinder with a smaller mass has a greater acceleration. In the case of equal masses, the accelerations are the same. We have indeed seen that the greater the mass, the less the acceleration.

3) Experimental task No. 2.

Take a ruler and place a coin on it. If you pull the ruler slowly, the coin will move with it.

Question: What happens to the coin if you suddenly pull out the ruler. Why?

4) Student messages

You can let students prepare the message “Interesting facts from the life history of I. Newton” in advance and listen to it in class (for about five minutes), or students can make a presentation about I. Newton.

5) Solving quality problems

Problems based on Newton's laws are suggested by life itself. Everyone has probably seen the cartoon “Well, wait a minute!” as a child. There was an episode: a wolf wants to catch up with a ship with a hare, gets into a sailboat and makes the boat move by blowing on the sail.

This folder contains video files (episodes from the cartoons “Well, Just Wait,” “The Adventures of Baron Munchausen”).

Slide No. 10

The slide contains a photograph of a wolf (<Рисунок1>), which blows into the sail. There is also a video file<Appendix 1> in the folder, which can be viewed if codecs for watching videos are installed. That is, instead of photos, you can show the corresponding application (In the presentation, I do not link to the video file, as it may not work).

Let's guys watch this episode. Tell me, does this situation correspond to what we talked about in class today? Discussion: According to Newton's third law, the air leaving the “wolf” acts on it with the same magnitude force as the air the wolf exhales. And it is with this force that the air acts on the sail. But the wolf and the boat with the sail are one. The forces turn out to be applied not to different bodies, but to one. These forces are equal in magnitude and opposite in direction. Their resultant is zero. And according to Newton’s first law, the speed of the body is a constant value, in this case zero.<Приложение1>

Slide No. 11

On the slide is a photograph of Baron Munchausen (<Рисунок2>), pulling his own hair. There is also a video file<Appendix 2>, which can be viewed if codecs for watching videos are installed. That is, instead of photos, you can show the corresponding application (In the presentation, I do not link to the video file, as it may not work).

Episode from the cartoon "The Adventures of Baron Munchausen". Baron Munchausen claimed that he pulled himself out of the swamp by his hair. Justify the impossibility of this. (Because the force acting upward on the head is equal to the force acting downward on the shoulder).<Appendix 2 >

Slide No. 12

The story of how “a swan, a crayfish and a pike started carrying a load of luggage” is known to everyone. And the result is also known,” but things are still there.” But if we consider this fable from the point of view of mechanics, the result is not at all similar to the conclusion of the fabulist Krylov. I remind you:

The swan rushes into the clouds,
Cancer is moving backwards
And the pike pulls into the water.

(The fable states that “the cart is still there,” in other words, that the resultant of all forces applied to the cart is equal to O. The swan helps the crayfish and the pike; its thrust is directed against gravity, it reduces the friction of the wheels on the ground and on the axles, thereby making it easier the weight of the cart. There are two forces left: the thrust of the crayfish and the thrust of the pike. They are directed at an angle to each other, and their resultant cannot be equal to zero).

The apple falls to the Earth because it is attracted by the globe; but with exactly the same force the apple attracts our entire planet to itself. Why do we say that the apple falls to the ground, instead of saying: “The apple and the ground fall on each other”? The apple and the earth actually fall on each other, but the speed of this fall is different for the apple and for the earth. Equal gravitational forces impart an acceleration of 10 m/s 2 to the apple, and to the globe - the same amount of times less, as the mass of the earth exceeds the mass of the apple. Of course, the mass of the globe is an incredible number of times greater than the mass of an apple, and therefore the earth receives a displacement so insignificant that it can practically be considered equal to 0).

How it feels in the shoulder when shooting from a rifle, why they make guns and carriages (the machines on which the gun is mounted) heavy.

4. Independent work

Testing students according to options followed by self-test (A. E. Maron, E. A. Maron: didactic materials grade 10)<Appendix 3 >

The test grade is assigned to all students according to the following criteria:

• "2" - 1 - 2 tasks
• "3" - 3 tasks
• "4" - 4 tasks
• "5" - 5 tasks

5. Summing up. Reflection on activities in the lesson.

Summing up the lesson. Grading.

The purpose of our lesson today was to repeat, generalize, consolidate and systematize Newton's laws. How are these laws formulated? (Answers.) At a qualitative level, by performing various experiments, we were convinced that these laws are correct, that they “withstood the test of experience.” From Newton's biography we know that at first he was a very mediocre student at school. And then one day he was offended by the best student in the class. Newton decided that the worst revenge for the offender was to take away his place as the first student. Newton's dormant abilities awoke, and he easily eclipsed his opponent.

The awakened genie of knowledge cannot be hidden again in a dark, moldy bottle. From that happy episode for world science began the process of transforming a modest English schoolboy into a great scientist.

I would like to hope that today’s lesson will also awaken your thirst for new knowledge, because the “great ocean of truth” still lies unexplored before you.

6. Homework

Slide No. 13

Paragraph 22-28 physics textbook 10th grade (G.Ya. Myakishev, B.B. Bukhovtsev, N.N. Sotsky)

Option 1.

Level A

What is the force that imparts an acceleration of 0.4 m/s to a body weighing 3 kg? 2 ?

With what acceleration did a jet aircraft weighing 50 tons move during takeoff? The thrust force of the engines is 80 kN.

A moving car in the horizontal direction is subject to an engine traction force of 1250N, a friction force of 600N and an air resistance force of 450N. What is the resultant of these forces?

What force must be applied to a turnip weighing 200 g in order to pull it out of the ground with an acceleration of 0.5 m/s2?

Level B

A skier weighing 60 kg, having a speed of 36 km/h at the end of the descent, stopped 40 s after the end of the descent. Determine the force of resistance to its movement.

A bullet weighing 7.9 g flies under the influence of powder gases from a barrel bore 45 cm long at a speed of 54 km/h. Calculate the average pressure force of the powder gases. Neglect the friction of the bullet against the walls of the barrel.

The electric locomotive develops a traction force of 700 kN. What acceleration will it impart to a train weighing 3000 tons if the resistance force to movement is 160 kN?

Option 2.

Level A.

A trolley weighing 200 kg moves with an acceleration of 0.2 m/s 2 . Determine the force imparting this acceleration to the trolley.

What is the acceleration with which a body of mass 3 kg moves if a force of 12 N acts on it?

The vessel is towed by three barges connected in series. The water resistance force for the first barge is 9000N, for the second – 7000N, and for the third – 6000N. The water resistance for the vessel itself is 11000N. Determine the traction force developed by the ship when towing these barges, assuming that the barges move uniformly.

A body weighing 4 kg is subjected to two horizontal forces, 10 N and 30 N, directed in opposite directions. Where and with what acceleration will the body move?

Level B

An empty truck weighing 3 tons began to move with an acceleration of 0.2 m/s 2 . What is the mass of this car together with the load if, with the same traction force, it moves away with an acceleration of 0.15 m/s 2 ?

A car weighing 2 tons is subject to a frictional force of 16 kN. What is the initial speed of the car if its braking distance is 50m?

A boy weighing 50 kg, sledding down a hill, drove along a horizontal road to a stop, a distance of 20 m in 10 s. What is the friction force acting on the sled?

Option 1.

Level A

1. What is the force that imparts an acceleration of 0.4 m/s2 to a body weighing 3 kg?

2. With what acceleration did a jet aircraft weighing 50 tons move during takeoff? The thrust force of the engines is 80 kN.

3. A moving car in the horizontal direction is subject to an engine traction force of 1250N, a friction force of 600N and an air resistance force of 450N. What is the resultant of these forces?

4. What force must be applied to a turnip weighing 200 g in order to pull it out of the ground with an acceleration of 0.5 m/s2?

Level B

1. A skier weighing 60 kg, having a speed of 36 km/h at the end of the descent, stopped 40 s after the end of the descent. Determine the force of resistance to its movement.

2. A bullet weighing 7.9 g flies under the influence of powder gases from a barrel bore 45 cm long at a speed of 54 km/h. Calculate the average pressure force of the powder gases. Neglect the friction of the bullet against the walls of the barrel.

3. An electric locomotive develops a traction force of 700 kN. What acceleration will it impart to a train weighing 3000 tons if the resistance force to movement is 160 kN?

Option 2.

Level A.

1. A trolley weighing 200 kg moves with an acceleration of 0.2 m/s2. Determine the force imparting this acceleration to the trolley.

2. What is the acceleration with which a body of mass 3 kg moves if a force of 12 N acts on it?

3. The vessel is towed by three barges connected in series. The water resistance force for the first barge is 9000N, for the second – 7000N, and for the third – 6000N. The water resistance for the vessel itself is 11000N. Determine the traction force developed by the ship when towing these barges, assuming that the barges move uniformly.

4. Two horizontal forces, 10 N and 30 N, directed in opposite directions, are applied to a body weighing 4 kg. Where and with what acceleration will the body move?

Level B

1. An empty truck weighing 3 tons began to move with an acceleration of 0.2 m/s2. What is the mass of this car together with the load if, with the same traction force, it starts from rest with an acceleration of 0.15 m/s2?

2. A friction force of 16 kN acts on a car weighing 2 tons. What is the initial speed of the car if its braking distance is 50m?

3. A boy weighing 50 kg, sledding down a hill, drove along a horizontal road to a stop a distance of 20 m in 10 s. What is the friction force acting on the sled?