Câu 20: Chọn câu sai:
A. Công là đại lượng vô hướng B. Công không có tính tương đối
C. Công phụ thuộc vào đường đi D. Công có giá trị đại số

Answers

Answer 1

Answer:

fr

Explanation:


Related Questions

PLZ HURRY ANSWER THIS PLZ
Which statement best describes how Greensburg recovered from the tornado? O A. It doubled its population O B. It secured itself against future tornadoes. C. It became an eco-tourism destination © D. It built a new school and hospital.​

Answers

Answer:

C: it became an eco-tourism destination

Explanation:

Answer: Its C

Explanation:

A rock falls to the ground with a force of 300N and air resistance pushes back up on the rock with a
force of 45N. Which is true of the rock?

Answers

Answer:

what are the choices

Explanation:

don't worry i'll edit it

four particles connected by rigid rods of negligible mass where y1 = 5.70 m. the origin is at the center of the rectangle. The system rotates in the xy plane about the z axis with and angular speed of 5.60 rad/s. a) calculate the moment of inertia of the system about the z axis. b) Calculate the rotational kinetic energy

Answers

The definition of moment of inertia and kinetic energy we can find the results for the questions are:  

          a) The moment of inertia is: I = 32.49 kg m²

          b) The kinetic energy is: K = 509.4 J

a) The moment of inertia is a scalar quantity that has the same function as mass, it is given by

             I = m r²

       

They indicate that the length of the bar is y₁ = 5.70 m, if the two rigid bars form the square that supports the masses, the distance from the center to the end where each mass is:  

            r = y₁ / 2

             r = 5.70 / 2 = 2.85 m

The moment of inertia of the system is.

         I = 4 m r²

Let's calculate.

        I =4 m 2.85²

        I = 32.49m kg m²

If we assume that the mass of each point particle is:

        m = 1 kg

   

         I = 32.49 kg m²

b) They ask for the rotational kinetic energy, if the angular velocity is.

           w = 5.60 rad / s

The kinetic energy for rotational motion is.

         K = ½ I w²

Let's calculate.

          K = ½ 32.49 5.60²

          K = 509.4 J

In conclusion with the definition of moment of inertia and kinetic energy we can find the results for the questions are:

          a) The moment of inertia is: I = 32.49 kg m²

          b) The kinetic energy is: K = 509.4 J

Learn more here:  brainly.com/question/14838079

Explain what occurs to satellites when they travel too fast and too slow to keep in orbit​

Answers

If the satellite goes too slow:

It will crash into it's surrounding things it's orbiting.It would not go forward enough due to pull of gravity.Gravity will pull it back to Earth.The satellite could be knocked or moved closer or farther from the object it is orbiting.

If the satellite goes too fast:

It will eventually fly away.It can go forward soo fast.It would go too fastly that gravity can't retain in an orbit.The satellite's inertia would carry it off into space.

helphelphelp due in 5 minutes answer the question below

Answers

The correct answer is B

if you double the force an object what will hapen to the accelration

Answers

Explanation:

the acceleration will double because force is directly proportional to the acceleration

A 20 kg box rests on the ground. Round all answers to the hundredths, if necessary. What is the weight of the box?​

Answers

Mass=m=20kgAcceleration due to gravity=10m/s^2

Weight=Applied force

[tex]\\ \sf\longmapsto F=mg[/tex]

[tex]\\ \sf\longmapsto F=20(10)[/tex]

[tex]\\ \sf\longmapsto F=200N[/tex]

Answer:

Weight=200

Explanation:

Given,

[tex]\sf\longmapsto \: mass = 20 \: kilograms[/tex]

We know that–

[tex]\sf\longmapsto \: acceleration \: \: because \: of \: gravity = 10m/s^2[/tex]

[tex]\sf\longmapsto \: Weight= \: is  \: F = m•g[/tex]

Let's start solving!

Weight = 20×10

Weight=200

What provides the centripetal force for the moon's orbit around Earth?​

Answers

Answer:

Gravitational attraction provides the centripetal force needed to keep planets in orbit around the Sun and all types of satellite in orbit around the Earth. This centripetal force is supplied by gravity. The Earth's gravity keeps the Moon orbiting us. Centripetal force is perpendicular to velocity and causes uniform circular motion. The gravitational attraction of the Sun is an inward force acting on Earth. This force produces the centripetal acceleration of the orbital motion. Centripetal forces are always directed toward the center of the circular path.

Explanation:

Answer: C.

the gravitational pull of the Sun

Explanation: plato :3

Hope this helps!

4. A gas's solubility is best in a liquid solvent when the solution is under high or low pressure

Answers

Answer:

low pressure

Explanation:

HELP HELP!


Which of the following surfaces would have the lowest amount of friction?

a. Glass
b. Sand
c. Wood
d. Ice

Answers

Answer:

d. Ice

Explanation:

Please show your workmkmmkekdmnesnndndndndn

Answers

Answer:

Explanation:

Remark

The question really is how long does the projectile stay in the air if it was just dropped from a height of 46 meters.

Givens

vi = 0

a = 9.81 m/s^2

h = 46 m

t = ?

Solution

d = vi*t + 1/2 a t^2

46 = 0 + 1/2 * 9.81 * t^2       multiply both sides by 2

92 = 9.81 * t^2                     divide by 9.81

t^2 = 9.38                            Take the square root of both sides

sqrt(t^2) = sqrt(9.38)

t = 3.06 seconds.

In 3.06 seconds the object will hit the ground, thus stopping it. How far horizontally does it go in that time.

d = r * t

d=?

r = 102 m/s

t = 3.06 seconds

d = 102 * 3.06

d = 312.4  meters.

dsfhfdskjhfdkshjkfdhskjdfhkjshjkfhsdkjf

Answers

Answer:

Abcdfeghijklmnopqrstuvwxyz

Explanation:

They are in order

When converted to a household measurement, 9 kilograms is approximately equal to a

Answers

Answer:

D) 19.8 lbs

Explanation:

1kg in household measurement is equal to 35.274 ounces. 35.274*9=317.466 ounces.

1kg is also equal to 2.205 lbs. 9*2.205=19.8416

9 kg is also equal to 9000 grams, but grams are not a part of the household measurement system

a) 9000 grams. b) 9000 ounces. c) 19.8 ounces. d) 19.8 pounds.

This leaves us with 19.8 lbs

can anyone heelp me pls pls

Answers

Answer:

Explanation:

Answer in the pic.. hope it helps

--[50 POINTS]--
1)A block of mass 25 kg is placed on flat ground. The coefficient of static friction and kinetic friction are 0.73 and 0.16
a.If a person pushes the block and the block is moving, what will be the acceleration of the block?


2) A block has a mass of 79 kg. The coefficient of static and kinetic friction between the sled and the ground is 0.87 and 0.37. Person A tries to pull the block with 210N, but fails.
a) Person B successfully pulls the sled with 909N. What is the acceleration of the sled?

Answers

Newton's second law allows us to find the results for the acceleration of the blocks are:

1) The acceleration is a = 559 m / s²

2) The acceleration is a = 7.88 m / s²

Newton's second law states that the net force is equal to the product of the mass and the acceleration of the body.

       ∑ F = m a

Where the bold letters indicate vectors, F is the force, m the mass and the acceleration of the body.

The reference system is a coordinate system with respect to which the decomposition of the forces is carried out, in the attached we have a free body diagram of the system.

1) They indicate that the body mass is 25 kg.

y-axis

       N - W = 0

       N = W = m g

x-axis

        F -fr = ma

The friction force is a macroscopic force that results from the sum of all the microscopic interactions between the two surfaces, it has the formula

        fr = μ N

Where fr is the friction force, N the normal and very the friction coefficient.

This friction coefficient has two values:

Static. For when with there is not relative motion between the two surfaces. Dynamic. When there is relative motion between the two surfaces.

We substitute.

         F - μ m g = m a

a) The system moves which is the acceleration.

Suppose that the force that star to move the system keeps constant, just before the system begins to move the coefficient of friction is static, let's find the applied force.

         F = μ m g

         F = 0.73 25 9.8

         F = 178.85 N

The block begins to move and the friction coefficient decreases to the dynamic value, we look for the acceleration.

         a = [tex]\frac{F - \mu \ m g}{m}[/tex]  

         a = [tex]\frac{178.85 - 0.16 \ 25 \ 9.8 }{25}[/tex]  

         a = 5.59 m / s²

2) In this case the mass of the block is 79 kg and the applied force is

        F = 909 N

We look for acceleration.        

        a = [tex]\frac{909 - 0.37 \ 79 \ 9.8 }{79}[/tex]  

        a = 7.88 m / S²

In conclusion using Newton's second law we can find the results for the acceleration of the blocks are:

         1) The acceleration is a = 559 m / s²

         2) The acceleration is a = 7.88 m / s²

Learn more here: brainly.com/question/11329269

Starting from rest, a student pulls a (25.0 A) kg box a distance of (4.50 B) m across the floor using a (134 C) N force applied at 35.0 degrees above horizontal. The coefficient of kinetic friction is 0.220 between the floor and the box. Find the work done by the pulling force. Give your answer in joules (J) and with 2 significant figures.

Answers

A 25.0 kg box is moved 4.50 m by a force of 134 N applied at 35.0° above horizontal. The work done by the pulling force is 4.9 × 10² J.

Starting from rest, a student pulls a 25.0 kg box a distance of 4.50 m across the floor using a 134 N force applied at 35.0 degrees above horizontal.

We can calculate the work  (W) done by the pulling force using the following expression.

[tex]W = F \times d \times cos\theta = 134 N \times 4.50 m \times cos35.0\° = 4.9 \times 10^{2} J[/tex]

where,

F: puling forced: displacementθ: angle between F and d

The friction between the floor and the box. does not influence the work done by the pulling force.

A 25.0 kg box is moved 4.50 m by a force of 134 N applied at 35.0° above horizontal. The work done by the pulling force is 4.9 × 10² J.

Learn more: https://brainly.com/question/25064916

A 3 kg drone starts at 5 meter above the ground and reached 25 meter above the
ground. Find the potential energy of the drone. Formula: PE=mghf-hi

Answers

Recall that work is the amount of energy transferred to an object when it experiences a displacement and is acted upon by an external force. It is given a symbol of W and is measured in joules (J).

W=\vec{F}\cdot \Delta \vec{d}

We can use this formula to determine the work done by very specific forces, generating specific types of energy. We will examine three types of energy in this activity: gravitational potential, kinetic, and thermal. Before we start deriving equations for gravitational potential energy and kinetic energy, we should note that since work is the transfer and/or transformation of energy, we can also write its symbol as \Delta E.

when air gets hot, it rises and forms…

Answers

Answer:

Gas

Explanation:

Hot air rises because gases expand as they heat up. When air heats up and expands, its density also decreases.

If a rock is thrown vertically upward from the surface of Mars with velocity of 20 m/s, its height (in meters) after t seconds is h = 20t − 1.86t2. (a) What is the velocity (in m/s) of the rock after 2 s? 12.56 Correct: Your answer is correct. m/s (b) What is the velocity (in m/s) of the rock when its height is 25 m on its way up? On its way down? (Round your answers to two decimal places.) up 8.07 Incorrect: Your answer is incorrect. m/s down -8.07 Incorrect: Your answer is incorrect. m/s

Answers

The velocity of the rock after 2s is 12.56 m/s.

The velocity of the rock at 25 m upwards is 14.68 m/s.

The velocity of the rock at 25 m downwards is -15.97 m/s.

The given parameters;

velocity of the rock, u = 20 m/sheight of the rock, h = 20t - 1.8t²

The velocity of the rock after 2s is calculated as follows;

[tex]v = \frac{dh}{dt}= 20 -2(1.86)t \\\\v = 20 - 3.72t\\\\at \ t= 2 \ s \\\\v = 20 - 3.72(2) = 12.56 \ m/s[/tex]

The velocity of the rock when the height is 25 m:

h = 20t - 1.8t²

25 = 20t - 1.8t²

1.8t² - 20t + 25 = 0

solve for the time of motion "t" using quadratic formula

a = 1.8,  b = -20,  c = 25

[tex]t = \frac{-b \ \ +/- \ \ \sqrt{b^2 - 4ac} }{2a} \\\\t = \frac{-(-20) \ \ +/- \ \ \sqrt{(-20)^2 - 4(1.8\times 25)} }{2(1.8)}\\\\t = 9.67s, \ \ or \ 1.43 \ s[/tex]

The value of t that will give 25 m upwards using the motion model is 1.43 s;

h = 20(1.43) - 1.86(1.43)² = 25 m

The velocity of the rock at 25 m upwards (t = 1.43 s) is calculated as follows;

[tex]v = \frac{dh}{dt} = 20 -3.72t\\\\v = 20 - 3.72(1.43) \\\\v = 14.68 \ m/s[/tex]

The velocity of the rock at 25 m downwards (t = 9.67 s) is calculated as;

[tex]v = \frac{dh}{dt} = 20 - 3.72t\\\\v = 20 - 3.72(9.67)\\\\v = -15.97 \ m/s[/tex]

Learn more here:https://brainly.com/question/25233377

I really need your help I will mark you brainliest!
I have been stuck for 15 minutes!!

Answer the following questions about Hurricane Harvey:
a. Why did hurricane Harvey travel from the east (Africia) twards the west (Florida) when our weather starts in the west and travels east?
B. why did hurricane harvey rotate counterclockwise? Do all hurricanes rotate counterclockwise?

Answers

https://www.lsop.colostate.edu/wp-content/uploads/sites/6/2014/10/HurricanesGoCounterclockwise.pdf

What forces act on an airplane to keep it in the air? If the airplane is traveling at a constant velocity, what could be said about the magnitudes of the forces? ​

Answers

Let's see

[tex]\\ \sf\longmapsto \overrightarrow{drag}[/tex]

[tex]\\ \sf\longmapsto \overleftarrow{Thrust}[/tex]

[tex]\\ \sf\longmapsto Lift\:Force\uparrow[/tex]

[tex]\\ \sf\longmapsto Acceleration\:due\:to\: gravity\downarrow[/tex]

Net force is 0

Question 2 of 10
You are riding a bicycle. If you apply a forward force of 125 N, and you and
the bicycle have a combined mass of 82 kg, what will be the forward
acceleration of the bicycle? (Assume there is no friction.)
A. 1.67 m/s2
B. 3.37 m/s2
C. 0.66 m/s2
D. 1.52 m/s2
O

Answers

Answer:

D - 1.52 m/s2

Explanation:

force: 125 N

Mass: 82 kg

you just divide the force by the mass which would be approximately 1.52

1. According to the picture, which is the least dense?
O A. the chess piece
O B. the toy soldier
O C. the liquid in the container
O D. There is no way to tell,

Answers

A chess piece is the less dense

According to the picture, the chess piece is the least dense. The correct option is A.

The amount of mass that a substance has in relation to its volume is referred to as its density. It is a measurement of how closely together the molecules or particles are arranged within a given object or material.

Typically, floating objects are less dense than the liquid they are in. The fact that the chess piece is floating on the water suggests that it is less dense than the liquid.

It might be an alternative, though, if the toy soldier is also floating and not submerged. More visual context is necessary for precise determination.

Thus, the correct option is A.

For more details regarding density, visit:

https://brainly.com/question/29775886

#SPJ3

PLEASE HELP ME!!!!!!!!!!!!!

Answers

Answer:

D gravity

Explanation:

please mark me brainliest

Answer:

D. The force that the branch applies to the kitten

Explanation:

I just took the quiz and got it correct!

Please HELP!!!!!!!!!!!!!!!!!!!!!

Using Newton's First Law, explain why, in a frictionless environment, a car that is under motion will not stop moving?

Answers

Answer:

According to Newton's first law of motion, an object maintains its state unless a force acts on it. Therefore, a moving car does not change its direction and keeps its speed unless a force acts on it.

what is the distance between a(-6,3),b(-2,4),c(-8,3)​

Answers

Answer:

Explanation:

Appears to be the vertexes of a triangle.

AB = √(-6 - (-2))² + (3 - 4)²) = √17

AC = √(-6 - (-8))² + (3 - 3)²) = 2

BC = √(-2 - (-8))² + (4 - 3)²) = √37

- The rocket now has a thruster that malfunctions and is now pushing the rocket in the wrong direction. What is the new net force on the rocket if it is now accelerating at 12mls²​

Answers

From your previous question

Mass=30kg

Acceleration=12m/s^2

[tex]\\ \sf\longmapsto F=ma[/tex]

[tex]\\ \sf\longmapsto F=30(12)[/tex]

[tex]\\ \sf\longmapsto F=360N[/tex]

Given,

Acceleration = 12 m/s²

According to your previous question you posted,

Mass = 30 KG

Solution:

We know that the formula of force according to the Newton's second law is:

[tex]\longmapsto \sf \red{f = m \times a}[/tex]

[tex]\sf \longmapsto \ 30 \times 12[/tex]

[tex]\sf \longmapsto \: \boxed {\sf \blue3 \red60}[/tex]

Answer:

[tex]\sf \boxed{ \bf \: force = 360\: N}[/tex]

2. In these diagrams, the sunlight is coming from the left, as shown by the arrows. Which
diagram is accurate and why? (1)

a) A is accurate because the half of the Moon that is facing the sun is it by the sun, and the
other half is dark.

b) B is accurate because the whole Moon is bright as long as there are no shadows
covering parts of it.

c) C is accurate because the Moon is almost as close as it can be to the sun, and so the
Moon is almost fully lit by the sun.

d) All three diagrams are sometimes accurate because the Moon has some lighter-colored
rock and some darker-colored rock, and the half of the Moon with the lighter-colored
rock rotates to face different directions.

Answers

Answer:

Explanation:

a) A is accurate because the half of the Moon that is facing the sun is it by the sun, and the other half is dark.

The most accurate diagram of the Sun and Moon is: a. A is accurate because the half of the Moon that is facing the sun is it by the sun, and the other half is dark.

What is a Moon?

A Moon can be defined as the natural satellite of planet Earth that shines due to the Sun's reflected light (sunlight), as it revolves around the Earth from west to east in 29½ days.

The phases of the Moon.

Based on astronomical information, there are four (4) primary Moon phases and these are:

New MoonFirst QuarterFull MoonThird Quarter (Last Quarter)

In conclusion, diagram A is the most accurate because half of the Moon that faced the Sun is lit by the Sun while the other half is dark.

Read more on Moon here: brainly.com/question/1286910

The term that is used to quantity the amount of heat in the evaporator is

Answers

Answer:

Enthalpy

The quantity of heat contained in a material as measured from a particular base or point.

Does bouncing or sticking produce more impulse?

Answers

Answer:

yes

Explanation:

Bouncing is a way to increase impulse. Because an object that bounces changes directions the force of impulse must be absorbed then generated by the target object. (Impulse is nearly doubled.)

Other Questions
PLEASE HELPPP, I WILL GIVE BRAINLIEST!!16. Why do Native American tribes have the right to fish, hunt, and gather resources on non-tribal lands?they don't, because people protestedthey retained those rights under treaties with the U. S. government in exchange for giving up land they occupiedthey bought the landthe land is in other states What is the estimated African population had the African slave trade not occurred? 400 million 200 million 1 billion100 million Which is the largest of the following numbers? 0.1, 0.02, 0.003, 0.0004, 0.00005 given that m 2 = 56 in the diagram what is m 8A 134B 66C 124 D 56 What is the greatest common factor of 8m2, 4m, and 10m4? Which group lists things that were unknown to Europe prior to the Colombian exchange? HELP HELP HELP HELP!!!!!!! Evaluate for a:69 = 13 - 7/12a 1 4/5 x 7 1/5 help mee What resulted from the agreement that ended the American Revolution?O Native Americans were offered land in the North.O Britain kept most of the land in the South.O Britain recognized the United States as its own country.O Native American groups were offered free passage to Britain. What are two main ideas of mesmerized some one please helpppppp I need answer asap!!!!!!!!!!! If you had been a delegate to one of the state conventions, would you have sided with the Federalists, or the Anti-Federalists? Use what you know about each group to support your own point of view and opinion.Please help, ive been having trouble please help if you dont know dont answer!!! Which of the following words would be found between the dictionary guide words measure and memory?mentalmealmembermetal i need a sentence with the word pathetically in it Based on what you know about the functions of bones, ligamentstendons and cartilage-which one will heal the fasted wheninjured? what is the equation of the line that passes through the point(-5,-4) and has a slope of -3/5? socio cultural features of geography Please Answer correctly true or false: akbar has created various ragas of music