9. A force is applied horizontally to a 20 kg box on a flat table, if the acceleration of the box is 2 m/s and the
coefficient of friction between the box and the table is 0.5, what was the magnitude (number) of the
applied force?

Answers

Answer 1

By Newton's second law,

n + (-w) = 0

p + (-f ) = (20 kg) (2 m/s²)

where n is the magnitude of the normal force, w is the weight of the box, p is the magnitude of the applied force (p for push or pull), and f is the magnitude of the friction force.

Calculate the weight of the box:

w = (20 kg) (9.80 m/s²) = 196 N

Then

n = w = 196 N

and

f = µ n = 0.5 (196 N) = 98 N

Now solve for p :

p - 98 N = 40 N

p = 138 N


Related Questions

Which arrow represents the centripetal acceleration?

Answers

Answer:

x

Explanation:

because the force on the car by gravity adds speed and acceleration.

Lvl 2: Select the passage which best describes the motion of the student.

Answers

Answer:

Ok I don't get you....

Explanation:

????

What is the frictional force between a box and the floor it is being pulled across if, the kinetic coefficient of friction is 0.27 and the box
weighs 38 N?
A 140.7 N
B 100.6 N
C. 37.7 N
D. 10.3 N

Answers

If the pulling is done parallel to the floor with constant velocity, then the box is in equilibrium. In particular, the weight and normal force cancel, so that

n = 38 N

The friction force is proportional to the normal force by a factor of 0.27, so that

f = 0.27 (38 N) ≈ 10.3 N

and so the answer is D.

What does "magnitude of the vector" mean?

Answers

Answer:

Explanation:

The magnitude of a vector is the length of the vector. The magnitude of the vector a is denoted as ∥a∥. See the introduction to vectors for more about the magnitude of a vector.

Formulas for the magnitude of vectors in two and three dimensions in terms of their coordinates are derived in this page. For a two-dimensional vector a=(a1,a2), the formula for its magnitude is

∥a∥=a21+a22‾‾‾‾‾‾‾√.

For a three-dimensional vector a=(a1,a2,a3), the formula for its magnitude is

∥a∥=a21+a22+a23‾‾‾‾‾‾‾‾‾‾‾‾√.

The formula for the magnitude of a vector can be generalized to arbitrary dimensions. For example, if a=(a1,a2,a3,a4) is a four-dimensional vector, the formula for its magnitude is

∥a∥=a21+a22+a23+a24‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾√.

Jorge asked, "Where are the apples?" Which sentence revises the sample sentence to the indicative mood? Where are the apples? Jorge wanted to know where the apples were. Jorge said, “Tell me where the apples are!” Jorge would have bought apples if he could have found them.

Answers

Answer:

Jorge wanted to know where the apples were

Explanation:

Ya see, I don't want to explain, cuz I guessed. Also I'm on episode 499 of naruto so yeah

Answer:

B:Jorge wanted to know where the apples were.

Explanation:

Plz answer these two questions. I am so sick.if u ddo it would mean a lot.

Answers

Gurlll same I hate physics

how do the early efforts of women during the suffrage movement compare to the later years

Answers

The idea that women's liberation is also men's liberation arouses the awakening of feminism. In 1966 Frieden and other feminists founded the National Organization for Women. Then other women's organizations for equal rights were formed in the United States and Western Europe. These organizations sought to overturn discriminatory laws and practices that forced women to hold down their status, such as discrimination in matters of contract and property ownership, employment and wages, the treatment of wage income, and issues relating to sex and child-bearing. The growing feminist movement more broadly seeks to change social stereotypes that women are more vulnerable, passive and dependent, less rational and emotionally reactive than men. Feminism strives for greater freedom for women in the workplace and makes them financially and psychologically independent of men, if they wish. Feminists criticized society's general emphasis on women as objects of sexual desire and sought to raise women's awareness and expand their opportunities in order to achieve equality with men. Another objective of feminism is to promote women's participation in all areas of political decision-making and social life.

Roberto has twice the mass his sister Mary has (see above) but runs at the same velocity as Mary. Will his kinetic energy be twice as much? Show your work. What happens to Roberto’s kinetic energy when he runs twice as fast?

Answers

Answer:

yes Robert's kinetic energy will be twice as much

if Robert runs twice as fast, then his KE will be 8 times Mary's KE

Explanation:

Kinetic energy KE = [tex]\frac{1}{2}[/tex]m[tex]v^{2}[/tex]

for Robert KE =  [tex]\frac{1}{2}[/tex](2m)[tex]v^{2}[/tex] =  m[tex]v^{2}[/tex]

for Mary KE = [tex]\frac{1}{2}[/tex]m[tex]v^{2}[/tex]

If you divide Robert KE by Mary KE = m[tex]v^{2}[/tex] /  [tex]\frac{1}{2}[/tex]m[tex]v^{2}[/tex] = 2; yes Robert's kinetic energy will be twice as much

if Robert v is equal to 2v

for Robert KE =  [tex]\frac{1}{2}[/tex](2m)[tex](2v)^{2}[/tex] =  4m[tex]v^{2}[/tex]

for Mary KE = [tex]\frac{1}{2}[/tex]m[tex]v^{2}[/tex]

If you divide Robert new KE by Mary's KE = 4m[tex]v^{2}[/tex] /  [tex]\frac{1}{2}[/tex]m[tex]v^{2}[/tex] = 8, if Robert runs twice as fast, then his KE will be 8 times Mary's KE

Roberto has twice the mass his sister Mary has (see above) but runs at the same velocity as Mary, then his kinetic energy would be twice that of Mary, and the kinetic energy of Roberto would be 8 times when he runs twice as fast Mary.

What is mechanical energy?

Mechanical energy is the combination of all the energy in motion represented by total kinetic energy and the total stored energy in the system which is represented by total potential energy.

The kinetic energy is the body depends on the mass as well as the speed of the object and is given by the mathematical expression as follows

K.E = 1/2 × m × v²

When Roberto runs at the same speed as his sister Mary but has twice Mary's mass (see above), Roberto's kinetic energy is twice Mary's, and it is eight times higher when Roberto runs twice as quickly as Mary.

To learn more about mechanical energy here, refer to the link given below ;

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For resonance to occur, the object must experience a frequency equal to its what?


period


wavelength


amplitude


natural frequency

Answers

Answer:

natural frequency

Explanation:

Answer: correct answer is {d}

Explanation: i got it right on my assesment

Given that on the moon g = 1.6 m/s2, and on Earth g = 9.8 m/s2, if a car on the moon weighs 3.8 N, what is its mass on Earth?

Do not write units in your answer, only numbers.

Round to one decimal place.

Answers

Answer:

The weight of the car on Earth is 19.6

Explanation:

The given parameters are;

The gravitational acceleration on the moon, [tex]a_{Moon}[/tex] = 1.6 m/s²

The gravitational acceleration on Earth, g = 9.8 m/s²

The weight of the car on the moon = 3.8 N

The weight of an object = The mass of the object, m × The gravitational acceleration acting on the object, g

The weight of the car = The mass of the car × The gravitational acceleration on the moon

∴ 3.8 N = The mass of the car × 1.6

The mass of the car = 3.8/1.6 = 2 kg

The weight of the car on Earth =The mass of the car × The gravitational acceleration on Earth, g

The weight of the car on Earth = 2 × 9.8 = 19.6

The weight of the car on Earth = 19.6.

Explanation: One can pick up a nail using the curved part of the horseshoe magnet farthest from the poles. A horse shoe magnet has magnetic fields all around it. In the presence of magnetic force fields, any magnetic object will be attracted to it.

Answers

Answer:

is there anymore choices than A

The white cue ball is moving towards the black 8 ball with a speed of 3.6 m/s. What is the momentum of the white cue ball? (p=mv)​

Answers

P=mv
Given :
v= 3.6 m/s^2
So
P=m * 3.6

How can people stop being Homophobia? °∩°

Answers

Pretty long so read if you will:

I'm pretty late to this but oh well. Well to start why are people homophobic in the first place? You might not understand as well but that is because me and you are growing up at a time and place where people are encouraged to be themselves and we're embracing people that are different than what is considered normal. Gay marriage was legalized literally in the US in 2015, 5 years ago. I come from Malaysia, one of the few countries where it's illegal to be gay and can cause a death penalty from what I've seen. Obviously I grew up in a place where gay and whatnot were a joke and is wrong. But we moved and I came to the US and my beliefs changes, it also helped that I was literally only 11 so I was more easier to change than adults. Majority of the world honestly, are not as open to the lgbtq+ community as a person in America might think. The belief that it's only a women and men probably stems from the fact that it's how u make babies. And if we know anything, society doesn't like things that are different. To stop people being homophobic you have to stop people from spreading the belief that it's wrong to be gay or bi. This is going to be hard and people really overestimate the world when it comes to change. Peoples belief won't be changed so quick just, change doesn't happen quick. It's going to be a long time and maybe even never, look at racism. We all exist together for so long but there's still racism though much less compared to back then. As long as people stop teaching that next generation, us, that being lgbtq+ is bad, it will decrease but it will take a long time. And as much as I agree we need it to be now, it won't and trying to force something will only cause more backlash. Just try to inform the people around you and understand change does not happen fast, it's slow, especially if it you want it to be permanent.

A cup is sliding down an inclined surface that is not smooth. What is the correct free body diagram for the body?

Answers

Answer:

Let's see the forces in the cup:

The gravitational force will act in the plane parallel to the inclined surface.

Because the surface is not smooth, we will have a friction force, which direction is opposite to the velocity vector.

The component of the gravitational force perpendicular to the surface is canceled with the normal force, so we will not have that in our diagram.

The correct option is not shown, so i will draw a simple sketch so you can identify the correct option:

Where the direction of the velocity is shown so we can know the direction of the friction force,

And we assume that both forces are applied on the center of mass, this is an oversimplified case, but this is the approach we usually take in this type of problems.

Answer:

For me it was B.    Fn is going to the NW.  Ff is going NE. Fg is going straight down.

Explanation:

I WILL MARK BRAINLIEST TO FIRST ANSWER IF CORRECT
In a battery (voltaic cell), in which direction does conventional current flow?

Answers

Answer:

In a discharging battery or galvanic cell (diagram at right), the anode is the negative terminal because it is where conventional current flows into the cell.

Explanation

In the lab. construct two half cells, one a zinc half cell and the other a copper half cell.

The zinc metal electrode will more readily ionise to Zn^2+  ion , then the copper metal.

This is because in the reactivity series zinc is more reactive metal.

Hence

connecting the two half cells, the zinc cell is put on the left and the copper half cell on the right.

Connect a wire and voltmeters between the electrodes, and a salt bridge between the two metal ion solutions.

Since the zinc is on the left and loses its electrons more readily the electrons flow from the electrode through the wire and voltmeter to the copper electrode.  So the electrons flow from r

left to right.

The conventional eq'n is

Zn|Zn^2+||Cu^2+|Cu

The electrons move into the copper electrode combine with copper solution to form more copper metal, which deposits on the copper electrode.

In a battery (voltaic cell), conventional current flow in the direction from positive to negative.

What is Current ?

Current is a flow of charges. it is denoted by i and expressed in ampere A.

Mathematically it is expressed as i = q/t, where q is the amount of charge and t is time. Current is nothing but amount of charges flown in the unit time in the electric wire. Charge is expressed in coulomb C and time in second s. hence coulomb per second (C/s) is ampere A. Charge on electron is 1.60217663 × 10⁻¹⁹ which is called as elementary charge.

There are two types of the current, Convectional current and non-conventional current.

Convectional current is the current flows from positive to negative. Non convectional current flows from negative to positive. Note that flow of electrons is from negative to positive.

Hence direction of flow of conventional current is from positive to negative.

To know more about electric current, click :

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What is the density of water?
gram/mL
(fill in the number)

Answers

Answer:

1.00 gram per milliliter (1 g/mL). In other words, 1 milliliter of water has a mass of 1 gram. A drop of water is 0.05 mL of water, so its mass would be 0.05 grams.

Explanation:

b) If the voltage of the fuel cell used in a circuit is 9.0 V and the resistance of the wire used in the circuit is 560 22,
what is the current running through the circuit? Use correct units at all times!
Formula:
Calculation:
Answer:
I

Answers

Answer:

current (I)=V/R

current (I)=9.0/56022

so I=1.607×10 in the power of negative four Amperes (A)

What is a population?

Answers

Answer:

:)

Explanation:

Population is how many people or citizens are in that country or continent.

PLZ EXPLAIN THE EQUATION AND I WILL GIVE BRAINLIST You are out and about in the country and your father sees a rock that he really wants in the yard. Now you must get the very heavy rock into the back of a truck. The truck bed is 3 feet off the ground. Your father pulls out a 5-foot plank and begins to set up a ramp. At the same time, you (who know about mechanical advantage!) have found a plank that is 8 feet long, and you show it to your father. Which plank will give you the most mechanical advantage? Calculate the MA for each plank

Answers

Answer:

The 8 foot long plank

Explanation: hope this helps :)

What are 2 laws of reflection

Answers

Answer:

The two laws of reflection are as follows: ... The incidenct ray, the reflected ray, and the normal to the reflecting interface at the point of incidence all lie in the same plane. 2. The angle of incidence equals the angle of reflection.

Angle of incidence and Angle of reflection hope this helps

Calculate the acceleration in meters per second-squared, of a car moving at 10 m/s that accelerates to 24 m/s over a time of 7 second--

Answers

Explanation:

v = u + at

24 = 10 + a * 7

24 = 10 * 7 a

a = 24 - 10/7

a = 14/7

a = 2m/sec^2

hope it helps you

Answer:

First calculate change in velocity:

final velocity = 20 m/s.

initial velocity = 30 m/s.

change in velocity = (20 - 30) = -10 m/s.

acceleration = -10 ÷ 25.

acceleration = -0.4 m/s 2

The acceleration value is negative here because the car is slowing down or decelerating.

Explanation:

why is SI unit established


Answers

Explanation:

The SI was established in 1960 by the 11th General Conference on Weights and Measures (CGPM, Conférence Générale des Poids et Mesures). The CGPM is the international authority that ensures wide dissemination of the SI and modifies the SI as necessary to reflect the latest advances in science and technology.

The space shuttle design team spent two years working with sketches and models before building the shuttle. Why were these steps important?



1.Sketches and models allowed for the design to be modified before investing huge amounts of time and money to build the actual shuttle.

2.Sketches and models allowed for many different astronauts to provide input on the design of the shuttle before investing money in the actual shuttle.

3.Sketches and models helped astronauts in their training program as they prepared for their missions.

Answers

Answer:

sketches and models helped astronauts in their training program as they prepare for their missions

Can you have p and KE with 0 kg mass why or why not?

Answers

No you cannot. For example, KE (kinetic energy) is defined by 1/2(m)(v^2). If mass is 0kg, KE would be equal to 0.

Whereas p, Potential energy is equal to mgh, which would also equal 0 if mass (m) were equal to 0.

What are the three forms of Newton’s 3rd Law?

Answers

Answer:

The third law states that all forces between two objects exist in equal magnitude and opposite direction: if one object A exerts a force FA on a second object B, then B simultaneously exerts a force FB on A, and the two forces are equal in magnitude and opposite in direction: FA = −FB.

Answer:

1 an object at motion will remain at motion and a object at rest will remain at rest until a outward force acts upon it

2 force is equal to mass multiple acceleration

3 if an object is acted on with a downward force the object will reflect with a same net force in the opposite direction

Explanation:

If the starting population of 5 rabbits grows at 200% each year, how many will there be 50 years?

Answers

Answer:

Alot of god dam rabbits

Explanation:

Answer:

million rabbits becauseeverything

The electromagnetic waves used in a microwave ovens has a frequency of 2540000000 Hz. The speed of the waves is 300000000 m/s. What is their wavelength?

Answers

Answer:

The wavelength of the waves is approximately 0.12 m.

Explanation:

An electromagnetic waves are generated as a result of the interaction between electric and magnetic fields. They do not require material medium for their propagation, and travel at the same speed (i.e the speed of light).

The speed, frequency and wavelength of a wave are related by:

speed = frequency x wavelength

wavelength = [tex]\frac{speed}{frequency}[/tex]

Given: speed of the wave = 3 x [tex]10^{8}[/tex], frequency = 2.54 x [tex]10^{9}[/tex].

Thus,

wavelength = [tex]\frac{300000000}{2540000000}[/tex]

                    = 0.11811

                    ≅ 0.12

wavelength ≅ 0.12 m

Therefore, the wavelength of the waves is 0.12 m.

n which phase(s) of matter are the atoms closely packed but still able to slide past each other?

gas
liquid
solid and gas
liquid and solid

Answers

Answer:

Liquid

Explanation:

The awnser is liquid because it is less densely packed and and therefore it slides past each other. Trust me the awnser is liquid

The depth of a circular well is 5m. water level is below 2m from the upper face of the wall. Find the pressure at its base ? (g=9.8m/ s²)​

Answers

Explanation:

Given, Depth = 5mReal depth of water = 5m - 2m = 3mg = 9.8 m/s2Pressure at its base =?

Now,

P = h d g = 3 × 1000 × 9.8 = 29400 pascal

Thats all,

The pressure at its base given the data from the question is 29400 Pa

Data obtained from the questionDepth = 5 mWater level = 2 mReal depth (h) = 5 - 2 = 3 mAcceleration due to gravity (g) = 9.8 m/s²Density of water (d) = 1000 Kg/m³Pressure (P) =?

How to determine the pressure

The pressure can be determined as follow

P = dgh

P = 1000 × 9.8 × 3

P = 29400 Pa

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Calculate the density of a rock that has a mass of 32 grams and a volume of

4.5 mL.

Answers

Answer:

85.2ml

Explanation:

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