S T A T I K A
Book's contents
1. Introduction.
2. THEORETICAL REVIEW.
3. DECISION TASK 1Unified State Examination - 55 TASK.
3-1. STRENGTH EQUALITY AND WEIGHT.
3-2. EQUALITY OF MOMENT POWER.
3-3. c ent r m a s s.
4. SOLUTION TO THE TASKH A S T I 2 Unified State Examination - 62 TASKS.
4-1. STRENGTH EQUALITY AND WEIGHT.
4-2. EQUALITY OF MOMENT POWER.
4-3. c ent r m a s s.
5. INDEPENDENT SOLUTION PROBLEMS - 10 tasks.
6. T A B L I C S F O R M U L A M I.
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AS AN EXAMPLE, THE BELOW ARE 4 PROBLEMS OUT OF 117 PROBLEMS ON THE TOPIC "STATICS" WITH DETAILED SOLUTIONS |
DECISION TASK PART 1 Unified State Examination
Problem No. 1-7
What should the strength be? F, so that the box can be moved evenly by the mass M= 60 kg lengthwise horizontal surface, if the coefficient of friction between the box and the platform μ = 0.27, and the force acts at an angle α = 30 o to the horizon?
Given: M= 60 kg, μ = 0,27, α = 30 o. Define F- ?
Rice. 4.
A box moving uniformly is acted upon by the following forces: Mg - gravity, F - traction force, F tr - friction force, N – the force of the normal reaction of the platform. Let us write the equation for Newton’s first law for the box: M g + F+Fmp+N = 0 . Let's project this equation onto the axes OX And OY:
OX: Fcosα - F tr=0 (1), OY: N + Fsinα – Mg = 0 (2).
From Eq. (2) let's express N = Mg – Fsinα, let's write down F tr = μN = μMg – μFsinα and substitute into the equation (1): Fcos α - μ Mg + μ Fsin α= 0.
R Let's solve this equation for forceF : Fcos α + μ Fsin α = μ Mg,
Problem No. 1-10
Body mass m 1 = 0.2 kg suspended from the right shoulder of a weightless lever (Fig. 1-2.8). What is the mass of the load? m 2, which must be suspended from the second division of the left arm of the lever to achieve balance and what is the tension force of the thread? T on which the rod is suspended?
Given: m 1 = 0.2 kg. Define m 2 - ? T - ?
Rice. 1 0 .
To prevent the rod from rotating around its suspension point, it is necessary that the sum of the moments of all external forces relative to this point be equal to zero. Let us write down the moments of forces relative to the suspension point.
Let us denote the distance between any two neighboring points rod through l .
Moment of power M 1 m 1 relative to the suspension point ABOUT equals M 1 = m 1 gd 1 = 4m 1 gl ,
Where d 1 = 4l – load gravity arm m 1 .
Moment M 1 rotates the rod clockwise.
Moment of power M 2 , created by force gravity of the load m 2 relative to the suspension point ABOUT equals
M 2 = m 2 gd 2 = 2m 2 gl ,
Where d 2 = 2l – load gravity arm m 2 . He rotates the rod counterclockwise.
Moment of power T relative to the suspension point ABOUT is equal to zero, since the line of action of this force passes through the point ABOUT.
Let us write the equilibrium equation for moments of forces:
M 2 – M 1 = 0 => 2 m 2 gl- 4 m 1 gl = 0.
From this equation we find the mass of the load that must be suspended from the left side of the rod so that the rod is in balance: m 2 = 2m 1 = 0.4 kg.
Since the rod does not move translationally, we write the force equation for the equilibrium of the rod in projections onto vertical axis:
T–m 1 g–m 2 g = 0, where do we find it from? T = m 1 g+m 2 g = 5.9 N.
DECISION TASK PARTICULAR 2 Unified State Exam
Problem No. 2-9
What angle α should be in the direction of the force with the horizon, so that when the load moves uniformly along a horizontal plane, the force F was the smallest? The force is applied at the center of gravity of the load, the friction coefficient is μ .
Given: μ. Define α at F min.
Rice. 9.
A load moving uniformly is acted upon by the following forces: Mg - gravity F - traction force, F tr - friction force, N - force normal reaction plane. Let us write the equation for Newton’s first law for the box: Mg + F + F tr + N = 0.
Let's project this equation onto the axes OX And OY:
OX: Fcosα - F tr=0 (1), OY: N + Fsinα – Mg = 0 (2).
From Eq. (2) let's express N = Mg – Fsinα, let's write down F tr = μ N = μ Mg - μ Fsinα and substitute into equation (1):
Fcosα - μ Mg + μ Fsinα = 0.
Solve this equation for force F :
Fcosα + μ Fsinα = μ Mg, where F = μMg/(cosα + μsinα) (3).
In the problem, you need to find the angle of direction of the force, provided that the force is minimal. To do this, we find the derivative of the force (3) by angle α and equate to zero
If the fractional equation is 0 , then the numerator of this fraction is equal to zero:
μcosα – sinα = 0, where tgα = μ and, finally, α = arctanμ.
Problem No. 2-24
Three masses m 1= 1 kg , m 2 = 2 kg and m 3= 3 kg are in equilibrium on a meter homogeneous rod mass m = 1 kg under gravity (Fig. 2.24). What is the distance? X?
Given: m 1= 1 kg , m 2= 2 kg, m 3= 3 kg, m= 1 kg, L= 1m, L 1 = 0.5 m. Determine X- ?
Rice. 2.24.
The equilibrium condition for the rod is the equation ∑M oi = 0, showing that the sum of the moments of all gravity forces relative to a point ABOUT equal to zero.
Let us write down the moment equation for this problem ∑M oi = M 1 + M 2 + M – M 3 = 0 ,
Where M 1 = m 1 gh 1 – moment of gravity of the mass m 1 relative to the point ABOUT, h 1 = (L – x) – gravity arm m 1 g ,
M 2 = m 2 gh 2 – moment of gravity of mass m 2 relative to the point ABOUT, h 2 = (L 1 – x) – gravity arm m 2 g,
M = mgh 2 - moment of gravity of the rod m relative to the point ABOUT, h 2 = (L 1 – x) – gravity arm mg ,
M 3 = m 3 gh 3 – moment of gravity of mass m 3 relative to the point ABOUT, h 3 = x – gravity arm m 3 g.
Let's rewrite the moment equation:
m 1 g(L – x) + m 2 g(L 1 – x) + mg(L 1 – x) - m 3 gх = 0 =>
Test
1. The spacecraft makes a soft landing on the Moon, moving slowly in the vertical direction (relative to the Moon) with constant acceleration 8.4 m/s2. How much does an astronaut weighing 70 kg weigh in this spacecraft if the acceleration on the Moon is 1.6 m/s2?
2. A brick weighing 2 kg was placed on an inclined plane with an inclination angle of 300. The sliding friction coefficient between the surfaces is 0.8. What is the frictional force acting on the brick?
3. The dog begins to pull a sled with a child weighing 25 kg with constant force 150 N, directed horizontally. What distance will the sled travel in 10 s if the coefficient of friction of the sled runners on the snow is 0.5?
4. On inclined plane A load weighing 26 kg lies 13 m long and 5 m high. The friction coefficient is 0.5. What force must be applied to the load along the plane in order to pull the load?
5. A box weighing 60 kg begins to be moved along a horizontal surface with an acceleration of 1 m/s2, acting on it with a constant force directed at an angle of 300 to the horizontal. Determine the force with which the box is pulled if the coefficient of sliding friction is 0.2.
Test
1. The spacecraft makes a soft landing on the Moon, moving slowly in the vertical direction (relative to the Moon) with a constant acceleration of 8.4 m/s2. How much does an astronaut weighing 70 kg weigh in this spacecraft if the acceleration on the Moon is 1.6 m/s2?
2. A brick weighing 2 kg was placed on an inclined plane with an inclination angle of 300. The sliding friction coefficient between the surfaces is 0.8. What is the frictional force acting on the brick?
3. A dog begins to pull a sled with a child weighing 25 kg with a constant force of 150 N directed horizontally. What distance will the sled travel in 10 s if the coefficient of friction of the sled runners on the snow is 0.5?
4. A load weighing 26 kg lies on an inclined plane 13 m long and 5 m high. The friction coefficient is 0.5. What force must be applied to the load along the plane in order to pull the load?
5. A box weighing 60 kg begins to be moved along a horizontal surface with an acceleration of 1 m/s2, acting on it with a constant force directed at an angle of 300 to the horizontal. Determine the force with which the box is pulled if the coefficient of sliding friction is 0.2.
The distance between the centers of the Earth and the Moon is 60 Earth radii, and the mass of the Moon is 81 times less than the mass of the Earth. At what point on the straight line connecting their centers will the body be attracted to the Earth and the Moon with equal forces?
Given: l=60R h, M 3 =81M L, R 3 = 6.4 10 6 m, F 1 = F 2.
Find: l 1
Solution. Let's find the gravitational forces F 2 between the body and the Earth and F l between the Moon and the body.
In law universal gravity
Since by condition F 1 = F 2, then
After extraction square root
QUESTIONS AND TASKS FOR SELF-CONTROL
1. Give examples when the Earth can be considered an inertial frame of reference.
2. What is meant by “inertia” and “inertia”?
3. How the body moves under the influence constant force?
4. The book is on the table. Identify the forces that obey Newton's third law.
5. Find the ratio of the accelerations of two iron balls when they collide, if the radius of the first ball is 2 times less than the radius of the second.
6. Why do the bodies in the room, despite their mutual attraction, not approach each other?
7. How can you find the mass of the Earth using the law of universal gravitation?
8. What deformations are described by Hooke’s law?
9. What is meant by absolute elongation? relative elongation?
10. Does the static friction force act on an object lying on a horizontal table? on an inclined plane?
11. What force holds the body on the rotating disk? How is it directed?
12. Does the braking distance of a car depend on its mass?
13. Under what conditions will a car at a curve in the road not be thrown onto the side of the road?
14. At what stage of movement spaceship will the astronaut feel the state of weightlessness?
15. Why is it advantageous to launch launch vehicles in the equatorial plane?
16. In the carriage of a uniformly and rectilinearly moving train, you hold a coin exactly above another similar coin lying on the floor. If you let go of a coin, where will it fall? The direction of movement of the train will be called forward direction.
17. A body weighing 2 kg moves with a speed of 6 m/s and an acceleration of 5 m/s 2 . What is the modulus of the resultant forces acting on the body?
18. A body weighing 4 kg is acted upon by forces F 1 = 3 N and F 2 = 4 N, directed to the south and west respectively. What is the acceleration of the body?
19. A car moves with acceleration a = 3 m/s 2 under the influence of two forces: engine traction force F 1 = 15 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?
20. Determine with what maximum acceleration a load weighing 200 kg can be lifted so that the rope can withstand maximum load 2500 N, did not burst.
21. What is the friction force if, after a push, a car weighing 15 tons stopped after 50 s, having covered a distance of 150 m?
22. A load weighing 5 kg is suspended from one end of a rope thrown over a block. With what force must the other end of the rope be pulled so that the load rises with an acceleration of 1.5 m/s 2?
23. At the ends of a weightless and inextensible thread thrown over a block, weights are suspended whose masses are 300 g and 200 g. Determine the speed of the weights 5 s after the system is left to its own devices.
24. A block of mass m rests on an inclined plane with an angle of inclination α. The sliding friction coefficient of the block on the inclined plane is μ. What is the friction force?
25. A box weighing 20 kg begins to move along a horizontal surface with an acceleration of 2 m/s2, acting on it with a constant force directed at an angle of 30° to the horizontal. Determine the force with which the box is pulled if the coefficient of sliding friction is 0.2.
26. The weight of an astronaut on Earth is 700 N. What is his weight in the rocket when moving with an acceleration of 4 g, directed vertically upward?
APPLICATION
1) In the carriage of a uniformly and rectilinearly moving train, you hold a coin exactly above another similar coin lying on the floor. If you let go of a coin, where will it fall? The direction of movement of the train will be called forward direction.
A) During the fall, the coin will move forward by inertia and fall in front of the coin lying on the floor.
B) The coin has inertia and when it falls, it will lag behind the coin lying on the floor moving with the train.
C) During the fall, the coin will move at the same speed as the train and will fall onto the lying coin.
D) The air moves with the carriage and carries the falling coin along with it. Therefore, the coin will fall onto the coin lying on the floor.
2) How does a body move if the sum of all forces acting on it is zero?
A) The speed of the body is zero.
B) The speed of the body decreases.
C) The speed of the body increases.
D) The speed of the body can be any, but it must be constant over time.
3) The figure shows the directions of the velocity vectors v and acceleration of the ball. Which of the presented directions has the vector of the resultant of all forces applied to the ball?
4) A body weighing 2 kg moves with a speed of 3 m/s and an acceleration of 2 m/s 2 . What is the modulus of the resultant forces acting on the body?
5) A body weighing 1 kg is acted upon by forces F 1 =9 N and F 2 =12 N, directed to the south and west, respectively. What is the acceleration of the body?
A) 15 m/s 2.
B) 30 m/s 2.
D) 25 m/s 2.
6) The car moves with acceleration a = 2 m/s 2 under the influence of two forces: the engine traction force F 1 = 10 kN and the 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?
7) Determine with what maximum acceleration a load weighing 120 kg can be lifted so that a rope that can withstand a maximum load of 2000 N does not break.
A) 3.2 m/s 2.
B) 6.4 m/s 2.
B) 12.8 m/s 2.
D) 1.6 m/s 2.
8) What is the friction force if, after a push, a car weighing 20 tons stopped after 50 s, having covered a distance of 125 m?
9) A load weighing 10 kg is suspended from one end of a rope thrown over a block. With what force must the other end of the rope be pulled so that the load rises with an acceleration of 2 m/s 2?
10) At the ends of a weightless and inextensible thread thrown over a block, weights are suspended whose masses are 600 g and 400 g. Determine the speed of the weights 2 s after the system is left to its own devices.
11) In a stationary elevator, there are two bodies on a spring scale and on an equal-arm scale with weights. How the readings will change: 1 - spring; 2 - scales with weights at accelerated movement elevator up?
A) 1 and 2 - will increase.
B) 1 and 2 - will decrease.
C) 1 - will not change, 2 - will decrease.
D) 1 - will increase, 2 - will not change.
12) Are the mass of a body and its weight the same when measured at the equator and at the pole?
A) Mass and weight are the same.
B) Both mass and weight are different.
C) The mass is different, the weight is the same.
D) The mass is the same, the weight is different.
13) How will the maximum force of static friction change if the force of normal pressure of the block on the surface is increased by 3 times?
A) Will not change.
B) Will decrease by 3 times.
B) Will increase by 3 times.
D) Will decrease by 1/3 times.
14) A block of mass m rests on an inclined plane with an angle of inclination α. The sliding friction coefficient of the block on the inclined plane is μ. What is the friction force?
15) A box weighing 60 kg begins to move along a horizontal surface with an acceleration of 1 m/s 2, acting on it with a constant force directed at an angle of 30° to the horizontal. Determine the force with which the box is pulled if the coefficient of sliding friction is 0.2.
16) The weight of an astronaut on Earth is 800 N. What is his weight in the rocket when moving with an acceleration of 3g directed vertically upward?
Home test
PART A
Choose one correct answer.
1) The plane flies in a straight line from constant speed at an altitude of 9 km. The reference frame associated with the Earth is considered inertial. In this case:
A) no forces act on the plane
B) the plane is not affected by gravity
C) the sum of all forces acting on the plane is zero
D) gravity is equal to the Archimedes force acting on the plane
2) A body weighing 1 kg is acted upon by forces of 6 N and 8 N, directed perpendicular to each other. What is the acceleration of the body?
3) A satellite of mass m moves around the planet in a circular orbit of radius R. The mass of the planet is M. What expression determines the value of the speed of the satellite?
4) A load weighing 2 kg was suspended from a spring 10 cm long, the stiffness coefficient of which is 500 N/m. What is the length of the spring?
5) A man was carrying a child on a sled along a horizontal road. Then a second child of the same type sat on the sled, but the man continued moving at the same constant speed. How did the friction force change in this case?
A) has not changed
B) decreased by 2 times
B) increased by 2 times
D) increased by 50%
6) A block slides down an inclined plane. Which vector shown in the figure is redundant or incorrect?
7) The velocity module of a car weighing 1000 kg changes in accordance with the graph shown in the figure. Which statement is true?
A) in section BC the car moved uniformly
B) in section DE the car was moving uniformly accelerated, the acceleration vector is directed opposite to the velocity vector
B) in section AB the car was moving uniformly
D) the acceleration module in section AB is less than the acceleration module in section DE.
8.Using the condition of the problem, match the equations from the left column of the table with their graphs in the right column.
Three bodies of equal mass, 3 kg each, performed movements. The displacement projection equations are presented in the table. Which graph shows the dependence of the projection of force on time acting on each body?
Solve problems.
9. A body of mass 10 kg suspended from a cable rises vertically. With what acceleration does the body move if a cable with a stiffness of 59 kN/m is lengthened by 2 mm? What is the elastic force generated in the cable?
10. The average height of the satellite above the Earth’s surface is 1700 km. Determine the speed of its movement.
11.Solve the problem.
A cart with a mass of 5 kg moves under the action of a weight with a mass of 2 kg. Determine the thread tension if the friction coefficient is 0.1.
LITERATURE
1. Firsov A.V. Physics for professions and specialties of technical and natural science profiles: textbook. – 2011.
2. Firsov A.V. Physics for professions and specialties of technical and natural science profiles: a collection of problems. – 2011.
3. Dmitrieva V.F. Problems in physics: textbook. – M., 2006.
4. Dmitrieva V.F. Physics: textbook. – M., 2006.
5. Gendenshtein L.E., Dick Yu.I. Physics. Textbook for 10th grade. – M., 2005.
6. Gendenshtein L.E. Dick Yu.I. Physics. Textbook for 11th grade. – M., 2005.
7. Gromov S.V. Physics: Mechanics. Theory of relativity. Electrodynamics: Textbook for 10th grade. educational institutions. – M., 2001.
8. Gromov S.V. Physics: Optics. Thermal phenomena. Structure and properties of matter: Textbook for 11th grade. educational institutions. – M., 2001.
9. Gromov S.V. Sharonova N.V. Physics, 10-11: Book for teachers. – M., 2004.
10. Kabardin O.F., Orlov V.A. Experimental tasks in physics. 9-11 grades: tutorial for students of general education institutions. – M., 2001.
12. Labkovsky V.B. 220 physics problems with solutions: a book for students of grades 10-11. educational institutions. – M., 2006.
13. Federal component state standard general education/ Ministry of Education of the Russian Federation. – M., 2004.
14. Kasyanov V.A. Physics. 10th grade: Textbook for general education educational institutions. – M., 2001.
Ticket No. 1
Mechanical movement. Uniform rectilinear movement. Equations of motion.
The law of universal gravitation.
A projectile flying in a horizontal direction at a speed of 600 m/s breaks into two parts with masses of 30 and 10 kg. Most of began to move in the same direction at a speed of 900 m/s. What is the magnitude and direction of the velocity of the smaller part of the projectile?
Ticket No. 2
Graphs of rectilinear uniform motion (coordinates, speeds, paths).
Gravity. First escape velocity.
A car weighing 1.5 tons moves at a constant speed of 27 km/h. The coefficient of resistance to movement is 0.02. How much power does the car engine develop?
Ticket No. 3
Instant and average speed.
Elastic force. Hooke's law. Types of deformations.
A stone is thrown from a height of 2 m at a certain angle to the horizontal initial speed 6 m/s. Find the speed of the stone as it hits the ground.
Ticket No. 4
Acceleration. Movement with constant acceleration. Equations of motion of a body with constant acceleration.
Friction and resistance forces.
A ball with a mass of 1 kg, moving at a speed of 6 m/s, catches up with a ball with a mass of 1.5 kg, moving in the same direction with a speed of 2 m/s. Find the velocities of the balls after their perfectly elastic collision.
Ticket No. 5
Charts uniformly accelerated motion(coordinates, speeds, accelerations).
Movement of connected bodies.
Two satellites move around the Earth in circular orbits at a distance of 7600 km and 600 km from its surface. What is the ratio of the speed of the first satellite to the speed of the second? The radius of the Earth is 6400 km.
Ticket No. 6
Free fall. Calculation of parameters in free fall.
Non-inertial reference systems.
The elevator descends with uniform acceleration and travels 10 m in the first 10 s. How much will the weight of a 70 kg passenger in this elevator decrease?
Ticket No. 7
The motion of a body thrown at an angle to the horizontal.
Force impulse and body impulse.
A cyclist weighing 80 kg moves on a loop ride at a speed of 54 km/h. The radius of the loop is 4.5 m. Find the weight of the cyclist at the top of the loop.
Ticket No. 8
The movement of a body thrown horizontally.
Law of conservation of momentum.
A column of troops during a march moves at a speed of 5 km/h, stretching along the road at a distance of 400 m. The commander, located at the tail of the column, sends a cyclist with an order to the lead detachment. A cyclist rides at a speed of 25 km/h and, having completed an errand on the move, immediately returns back at the same speed. How long after receiving the order will he return?
Ticket No. 9
Uniform movement points around the circle. Centripetal acceleration.
Work of force. Power.
A ball is thrown out of a window horizontally at a speed of 12 m/s. He fell to the ground after 2 s. From what height was the ball thrown and how far from the building did it land?
Ticket No. 10
Relativity of mechanical motion. Galileo's principle of relativity.
Energy. Law of conservation of energy in mechanics.
Determine the average orbital speed satellite, if average height its orbit above the Earth is 1200 km, and its orbital period is 105 minutes.
Ticket No. 11
Newton's first law. Inertial systems countdown.
Change in energy of the system under the influence external forces.
A wooden block with a mass of 2 kg is pulled uniformly over a wooden board placed horizontally using a spring with a stiffness of 100 N/m. The friction coefficient is 0.3. Find the extension of the spring.
Ticket No. 12
Resultant force. Newton's second law.
Absolutely elastic collisions of balls.
A person weighing 60 kg stands on ice and catches a ball with a mass of 500 g, which flies horizontally at a speed of 20 m/s. How far will a person with a ball roll on a horizontal ice surface if the coefficient of friction is 0.05?
Ticket No. 13
Newton's third law. Body weight.
Absolutely inelastic collisions balls.
A box weighing 60 kg begins to move along a horizontal surface with an acceleration of 1 m/s 2 , acting on it with a constant force directed at an angle of 30 0 to the horizon. Determine the force with which the box is pulled if the coefficient of sliding friction is 0.2.
Questions for the 10th grade physics test.
- What do they call mechanical movement? What's happened material point and why this concept was introduced.
- What is a reporting system? Why is it introduced?
- What is the average speed of alternating motion called?
- What is acceleration called?
- What do they call instantaneous speed uneven movement?
- Write formulas describing uniformly accelerated rectilinear motion.
- Write formulas for the coordinates of a body during uniformly accelerated rectilinear motion
- What is called free fall of a body? Under what conditions can falling bodies be considered free?
- What type of motion is the free fall of bodies?
- Does the acceleration of gravity depend on mass?
- Write formulas describing the free fall of bodies.
- State Newton's laws? What are the features of Newton's laws?
- What is the direction of the acceleration of the body caused by the acting force?
- Under what conditions is it fair? classical law speed addition?
- What is the relativity of the motion of bodies? Give examples.
- What is the principle of independence of forces?
- What types of interactions exist in nature? Which of these relates to the interaction leading to the appearance of elastic force?
- What is the formula for the law of universal gravitation?
- Does the force of gravity depend on the properties of the medium in which all bodies are located?
- What is the classification of the main types of sliding friction coefficient? What does its meaning depend on?
- What is the coefficient of sliding friction? What does its meaning depend on?
Tasks for testing.
- The distance between the two piers is 144 km. How long will it take the steamer to complete the voyage there and back if the speed of the steamer in still water is 13 km/h and the speed of the current is 3 m/s?
- When braking, the car reduced its speed from 54 to 28.8 km/h in 7 seconds. Determine the acceleration of the car and the distance traveled when braking.
- Determine the mass of a body to which a force of 50N imparts an acceleration of 0.2 m/s 2 . What displacement did the body make in 30 s from the beginning of the movement?
- The traction force acting on the car is 1 kN, the moving resistance force is 0.5 kN. Doesn't this contradict Newton's third law?
- A car weighing 3 tons, having a speed of 8 m/s, is stopped by braking after 6 s. Find the braking force.
- Two students pull on a dynamometer in opposite sides. What will the dynamometer show if the first student can develop a force of 250 N, and the second - 100 N?
- A football player hits a ball with a mass of 700 g and gives it a speed of 12 m/s. Determine the force of the impact, considering it to last 0.02 s.
- A box weighing 60 kg begins to move along a horizontal surface with an acceleration of 2 m/s 2 . Acting on him with a constant force. Determine the force with which the box is pulled if the coefficient of sliding friction is 0.2
- The radius of the planet Mars is 0.53 Earth radii, and its mass is 0.11 Earth masses. Knowing the acceleration free fall on Earth, find the acceleration due to gravity on Mars.