A. The faster the speed of the same car, the more difficult it is to brake, indicating that the higher the speed of the object, the greater the inertia.

B. an object has inertia only when it is at rest or moving in a straight line at a constant speed.

C table tennis can be killed quickly because of its small inertia.

D It is known that the acceleration of gravity on the moon is 1/6 on the earth, so the inertia of an object moving from the earth to the moon is reduced to 1/6.

2. The following statements about particles are correct.

A. The nucleus is very small, so it can be regarded as a particle. B. When studying and observing the solar eclipse, the sun can be regarded as a particle.

C. when studying the earth's rotation, we can regard the earth as a particle. D. when studying the revolution of the earth, you can regard the earth as a particle.

3. Which of the following units belongs to the basic unit in the international system of units?

A. meter, Newton, kilogram, joule, second, meter, kilogram, second.

The following statement is correct.

A. As long as two objects touch, they will produce elastic force. B. The supporting force of the object placed on the desktop is caused by the deformation of the desktop.

C. the direction of sliding friction is always opposite to the direction of motion of the object. The center of gravity of a regularly shaped object must coincide with its geometric center.

5. In the 100 meter race, an athlete's instantaneous speed at the end of 5s is10.4m/s, and at the end of 60s is10.2m/s ... So his average speed in this race is

A.10m/s10.2m/s10.3m/s

6. Hold the bottle by hand so that it is still in the vertical direction. If the grip strength is doubled, the friction between the hand and the bottle will decrease.

A. the greater the grip strength, the greater the friction. B As long as the bottle doesn't move, the friction has nothing to do with the previous factors.

C. the direction changes from downward to upward. D. The drier and rougher the hand, the greater the friction.

7. After being impacted, the object M slides upward along an unsmooth slope, as shown in the figure. In the process of sliding, the force on the object M is:

A. Gravity, upward impulse along the inclined plane and supporting force of the inclined plane

B. Gravity, sliding friction along the inclined plane and supporting force of the inclined plane.

C gravity, impulse upward along the inclined plane and sliding friction downward along the inclined plane.

D gravity, upward impulse along the slope, downward friction along the slope, and supporting force of the slope.

8. The three forces in the same plane are 4N, 6N and 7N respectively. If three forces act on an object at the same time, the maximum and minimum values of the resultant force of the three forces on the object are respectively

a . 17N 3N b . 5n 3N c . 9n 0d . 17N 0

9. When the car travels in a straight line between two stations, it starts from Station A, first travels at a constant speed of V for half the distance, and then slows down for the second half. When it arrived in bilibili, the speed was exactly zero, so the average speed of the car during the whole trip was

AC/3V AC/2V AC/3V DC/2V DC

10. At the Winter Olympics in Turin, which closed on February 26th, 2006, Zhang Dan and Zhang Hao won the silver medal in synchronized skating with perfect performance. At the beginning of the skating performance, they stood still and moved in the opposite direction with the beautiful music. Assuming that the friction coefficient between their skates and the ice is the same, we know that Zhang Dan skates farther than Zhang Hao on the ice. This is because.

A. In the process of pushing, the force of Zhang Dan pushing Zhang Hao is less than that of Zhang Hao pushing Zhang Dan.

B in the process of pushing, Zhang Hao pushed Zhang Dan for a longer time than Zhang Dan pushed Zhang Hao.

C. At the time of separation, the initial velocity of Zhang Dan is greater than that of Zhang Hao.

After separation, the acceleration of Zhang Dan is greater than that of Zhang Hao.

Multiple choice questions: (There are four options for each question, and there is more than one correct one. Please fill in the correct answer on the answer sheet. 4 points for each small question, 2 points for missing answer, and 0 point for wrong choice. *** 16)

1 1. As shown in the figure, the ball hanging on the ceiling of the car deviates from the vertical angle θ, so the movement of the car may be as follows.

A. Right acceleration movement B. Right deceleration movement C. Left acceleration movement D. Left deceleration movement

12. In the following sports, there may be:

A. the speed changes greatly and the acceleration is very small; B. The direction of speed change is positive and the direction of acceleration is negative;

C. the speed is getting bigger and bigger and the acceleration is getting smaller and smaller. D. the speed changes faster and faster, and the acceleration becomes smaller and smaller;

13. The picture shows the v-t image of two objects A and B moving linearly from the same place to the same direction at the same time. From the image, we can know that

A.a moves at a uniform speed, and b moves at a uniform speed.

B.a and b meet at the end of B.20s

At the end of C.C.20s, A and B are the farthest apart.

D.a and b meet at the end of d.40.

14. As shown in the figure, there are two blocks, M and M, on the smooth desktop. Now push the block M with force F, so that the two blocks accelerate to the right together on the table. Then the interaction between m and m is as follows:

A. Master of Biomedicine

C. If the friction coefficient of the desktop is 0, M and M are still accelerating to the right, and the interaction force between M and M is

D. If the friction coefficient of the desktop is 0, M and M are still accelerating to the right, and the interaction force between M and M is still 0.

Volume II (54 points)

3. Fill in the blanks: (* *12)

Dynamic friction coefficient of materials

Metal-metal 0.25

Rubber-metal 0.30

Wood metal 0.20

Leather-Metal 0.28

15. As shown in the figure, one end of the spring dynamometer is fixed on the wall, and the metal plate is horizontally pulled to the left by the force F, and the metal plate moves to the left. At this time, the indicator of the dynamometer is stable (the indicator of the spring dynamometer has been enlarged in the figure), so the sliding friction between the block P and the metal plate is n. If the weight of the block P measured by the spring dynamometer is 13N, the material of the block P can be calculated according to the dynamic friction coefficient given in the table.

16. Use a point timer connected to a 50Hz AC power supply to measure the acceleration of a car moving in a straight line, and get the paper tape as shown in the figure. Starting from a clear point, take several counting points and mark them with 0, 1, 2, 3 ... respectively (four printing points are not marked between every two adjacent counting points), and get two points, namely 0 and 1. The distance between 3 and 4 is x4=48 mm, so the average speed of the car between 0 and 1 is m/s, and the acceleration of the car is m/s2.

4. Calculation problem: (This topic is ***4 small questions, with ***42 points. The necessary words, equations and important calculation steps should be written for the solution. Only write the final answer without grading. If there is a problem with numerical calculation, the numerical value and unit must be clearly written in the answer. )

17(8 points) The car that started to move in a straight line at a constant speed at rest passed the displacement of 0.4m within1s. Q: What was the speed at the end of (1) 1s? ⑵ What is the displacement of the car in the second second?

18( 10 minutes) There is a spring scale hanging on the ceiling of the elevator that rises and falls vertically. As shown in the figure, an object with a mass of m = 4 kg is hung on the hook of the spring scale. Try to analyze various specific actions of the elevator under the following conditions (g is 10m/s2):

(1) When the indicator T 1=40N = 40N of the spring scale remains unchanged.

(2) When the indicator T2 of the spring scale is 32n and remains unchanged.

(3) When the indicator T3 of the spring scale is 44n, it remains unchanged.

19( 10 minute) As shown in the figure, there is a horizontal conveyor belt moving at a constant speed of 2m/s, and now an object is gently placed on the left end of the conveyor belt. If the dynamic friction coefficient between the object and the conveyor belt is 0.5 and the distance between the left and right ends of the conveyor belt is known as 10m, the time required for the conveyor belt to transport the object to the right end of the conveyor belt is calculated. (g = 10m/s2)

20( 14 minutes) As shown in the figure, use a rope to hang a ball with a mass of 4kg on the back wall of a moving car, and the angle between the rope and the vertical direction is 37? . G = 10m/s2, sin37? =0.6，cos37？ =0.8, and:

(1) When the car is moving at a uniform speed, the tension of the thin wire on the ball and the pressure of the back wall of the car on the ball.

(2) When the car decelerates to the right at a speed of a=2m/s2, the tension of the thin thread on the ball and the pressure of the ball on the back wall of the car.

(3) When the car is driving at a speed of a= 10m/s2, the tension of the thin thread on the ball and the pressure of the ball on the rear wall of the car.

20( 14 minutes) As shown in the figure, use a rope to hang a ball with a mass of 4kg on the back wall of a moving car, and the angle between the rope and the vertical direction is 37? . G = 10m/s2, sin37? =0.6，cos37？ =0.8, and:

(1) When the car is moving at a uniform speed, the tension of the thin wire on the ball and the pressure of the back wall of the car on the ball.

(2) When the car decelerates to the right at a speed of a=2m/s2, the tension of the thin thread on the ball and the pressure of the ball on the back wall of the car.

(3) When the car is driving at a speed of a= 10m/s2, the tension of the thin thread on the ball and the pressure of the ball on the rear wall of the car.

Reference answer

First, multiple-choice questions:

The title is 1 23455 6789 10.

Answer c d c b b b d c c

2. Multiple choice questions:

Title:11121314.

Answer AD ACACDBD

3. Fill in the blanks:

15.2.60 N (2.6 also points) wood

16.0.3; 0.6

4. Calculation problems:

17.(8 points)

Solution: the car moves in a straight line with uniform acceleration, and the initial speed is zero.

(1) from, get:-(3 points)

Then the speed at the end of 1s is v1= at = 0.8×1m/s = 0.8m/s-(2 minutes).

(2) From s 1∶s2= 1∶3, we get:

The displacement of vehicles passing within 2s is S2 = 3s1= 3x0.4m =1.2m-(3 points).

There are many ways to solve this problem. Please define and unify the standards by the marking group. )

18.( 10)

Solution: choose the object as the research object, and the force analysis is shown in the figure. (abbreviated) —— Figure: 1.

(1) When t 1 = 40n, according to Newton's second law, t 1-mg = ma 1, (1 min) is obtained.

Acceleration of the elevator at this time (1 point)

It can be seen that the elevator is in a static or uniform linear motion state. (1 min)

(2) When t2 = 32n, according to Newton's second law, there is t2-mg = ma2, (1 point) to get this solution.

Acceleration of the elevator at this time (1 point)

That is, the acceleration direction of the elevator is vertical downward. The elevator speeds up or slows down. ( 1)

(3) When t3 = 44n, according to Newton's second law, t3-mg = ma3 is obtained.

Acceleration of the elevator at this time (1 point)

That is, the acceleration direction of the elevator is vertical upward. The elevator speeds up or slows down. ( 1)

19.( 10)

Solution: When an object is placed at the left end of the transmission belt, it will make an accelerated linear motion first. The stress analysis is shown in figure (1), which is obtained by Newton's second law:

( 1)

Alternate data score: (1)

When the object accelerates to a speed equal to the conveyor belt speed v = 2 m/s,

Exercise time (2 points)

Motion displacement (1 point)

Then the object will do uniform linear motion, and the time required for uniform linear motion is:

(2 points)

Time required for the object to reach the right end of the conveyor belt (2 points)

20.( 14 points)

Solution: When (1) moves at a uniform speed, the force analysis of the ball is shown in the figure (omitted), which is obtained from the equilibrium condition:

Alternative data:,

(2) When the car decelerates to the right at a speed of a=2 m/s2, the force analysis of the ball is shown in the figure (omitted), which is obtained by Newton's second law:

Alternative data:,

(3) When the car decelerates to the right at a uniform speed, the acceleration (critical condition) is a0 when the elasticity of the rear wall of the car is 0, and the force analysis is shown in the figure, which is obtained from Newton's second law:

Alternative data:

Because, so the ball can fly. Let the angle between the rope and the vertical direction be, which is obtained by Newton's second law: