A 10 kg box initially at rest is pulled with a 50 N horizontal force for 4 m across a level surface. The force of friction acting on the box is a constant 20 N. How much work is done by the normal force pushing up on the box from the ground?
A. 10 J
B. 0 J
C. 100 J
D. 50 J

Answers

Answer 1

Answer: 0 j

Explanation:

It is given that,

Mass of the box, m = 10 kg

Force with which the box is pulled, F = 50 N

It is moved a distance of 4 m

Force of friction acting on the box, f = 20 N

We need to find the initial kinetic energy the box have. It is clear that the box is at rest initially. As there is no motion in the box at that time. The formula for the kinetic energy of the box is given by :

As v = 0

So, the initial kinetic energy of the box is 0. Hence, this is the required solution.  


Related Questions

Surface tension is often calculated using a machine that lifts a wire ring from the surface of a liquid. In this case the ring and liquid have some cohesive forces and attract rather than repel. In order to lift a ring of radius 2.75 cm off of the surface of a pool of blood plasma, a vertical force of 2.00*10-2 N greater than the weight of the ring is required. Consider the situation just before the ring breaks contact with the blood plasma where the blood plasma makes a contact angle of approximately zero degrees along the circumference of the ring and is stretched down vertically on both sides of the ring.

Required:
Calculate the surface tension of blood plasma from this information.

Answers

Answer:

0.116 N/m

Explanation:

Since the net force acting on the ring must be greater than 2.00 × 10⁻² N, and the surface tension T = F/L where F = net force = 2.00 × 10⁻² N and L = circumference of ring = 2πr where r = radius of ring = 2.75 cm = 2.75 × 10⁻² m.

So, T = F/L

= F/2πr

= 2.00 × 10⁻² N ÷ 2π(2.75 × 10⁻² m)

= 1/2.75π  N/m

= 1/8.64 N/m

= 0.116 N/m

A potter's wheel is a uniform disk of mass 4.50 kg and radius 0.650 m and can spin freely around a vertical axis through its center. With the wheel spinning at an angular speed of 4.70 rad/s, a small piece of clay of mass 0.870 kg is dropped at the outer edge of the wheel and sticks to it. Find the final angular speed of the wheel clay. Treat the piece of clay as a point particle. Group of answer choices

Answers

Answer:

3.39 rad / s.

Explanation:

Given data:

mass of disk = 4.50 Kg

radius of wheel = 0.650 m

mass of the clay = 0.870 kg

The moment of inertial of the wheel = I = 4.5 kg x ( 0.65 m )2 / 2 = 0.95 kg . m2.

Now, applying the principle of angular momentum conservation :

Iω_i = ( I + mr2 )ω_f.

where ω_i = initial angular speed= 4.70 rad/s, ω_f = final angular speed

Hence, ω_f = Iω_i / ( I + mr2 )

= ( 0.95 kg . m2 x 4.7 rad / s ) / [ 0.95 kg . m2 + 0.87 kg x ( 0.65 m )2 ]

= 3.39 rad / s.

Hence, correct answer is  : 3.39 rad / s.

What kind of weather would MOST LIKELY lead to hurricane formation?

Answers

Answer:

The recipe for a hurricane is a combination of warm, humid wind over tropical waters. The temperature of tropical waters must be at least 80 degrees F for up to 165 feet below the ocean’s surface. As this warm water meets the wind that blows west from Africa across the ocean, it causes the water to vaporize. The water vapor then rises into the atmosphere, where it cools and liquefies.

Explanation:

I hope this helps

1. A person kicks a rock off a cliff horizontally with a speed of 20 m/s. It takes 7.0 seconds to hit the
ground, find:
a. height of the cliff
b. final vertical velocity
C. range
D.speed and angle of impact

Answers

This problem involved half projectile.

initial velocity, vo = 20 m/s

time of flight, t = 7 s

(a) Simply use the formula to get the height, h:

h = vo*t - (1/2)gt^2

(b) To get the final vertical velocity or terminal velocity (vf), use the formula:

(vf)^2 - (vo)^2 = 2gh

(c) Use the formula find the horizontal distance traveled, R:

R = vo * cos(θ) * t

But since the angle involved with respect to horizontal is zero, and cos(0) = 1, we have

R = vo * t

Hope this helps~ `u`

Jai

A farmer plants the same crop in a field year after year. Every year there are months during which the field is left without any plants. The farmer notices a decline in soil
quality during these months. What causes this decrease in soil quality?
Erosion
Drought
Desertification
Consumption of nutrients by the crops

Answers

Answer:

Drought

Explanation:

A graduated beaker with 375 mL of water is sitting on a scale which measures the weight of the glass and water to be 7.60 N. When a rock is put into the glass, the volume level of the water changes to 450 mL and the scale reading changes to 9.22 N. What is the specific gravity of the rock

Answers

Answer:

Volume of water displaced = 450 - 375 = 75 ml

Vr = volume of rock = 75 ml

Wr = 9.22 - 7.60 = 1.62 N  weight of 75 ml of rock

Density of rock = 1.62 N / 75 ml = .0216 N / ml

Density of water = 1000 g / 1000 ml = 9.8 N / 1000 ml = .0098 N / ml

Density of rock / density of water = .0216 / .0098 = 2.20

The specific gravity of the rock in the given water volume is 0.2.

The given parameters;

initial volume of the water, = 375 mlweight of the water, = 7.6 Nfinal volume of water = 450 mlchange in scale reading = 9.22 N

The specific gravity of the rock is calculated as follows;

[tex]S.G = \frac{weight \ in \ air}{Weight \ in \ water} \\\\S.G = \frac{450 - 375}{375} \\\\S.G = 0.2[/tex]

Thus, the specific gravity of the rock in the given water volume is 0.2.

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Cathode ray tubes (CRTs) used in old-style televisions have been replaced by modern LCD and LED screens. Part of the CRT included a set of accelerating plates separated by a distance of about 1.40 cm. If the potential difference across the plates was 23.0 kV, find the magnitude of the electric field (in V/m) in the region between the plates.

Answers

Answer:

E =  1.64 x 10⁶ V/m

Explanation:

The electric field in the region between the plates can be given by the following formula:

[tex]E = \frac{\Delta V}{d}[/tex]

where,

E = Electric Field = ?

ΔV = Poetential Difference across the plates = 23 KV = 23000 V

d = distance between plates = 1.4 cm = 0.014 m

Therefore, using these values in the equation, we get:

[tex]E = \frac{23000\ V}{0.014\ m}[/tex]

E =  1.64 x 10⁶ V/m

A vessel having a capacity of 0.05 m³ contains a mixture of saturated water an saturated steam at a temperature 245°C the mass of the liquid present is 10 kg. find the following: i- The pressure. ii- The mass. iii- The specific volume. iv- The specific enthalpy. v- The specific internal energy.

Answers

b because because i’m was not a big head of a baby i i would’ve got caught up in here and he did it again i

A projectile was fired horizontally from a cliff 20m above the ground. If
the horizontal range of the projectile is 40m, calculate the initial velocity
of the projectile.

Answers

The initial velocity of the projectile is 19.8m/s

Explanation:

First, find time.

From our kinematics equations:

delta y = Vi•t + (1/2)at^2

rearrange,

t = sqrt[(2•delta y)/a]

t = sqrt[(2•20m)/9.8m/s^2]

t = 2.02s

Next, plug time into new kinematics equation to solve for the Vi in the x direction (horizontal)

delta x = Vi•t + (1/2)at^2

delta x = Vi•t

Rearrange:

Vi = delta x/t

Vi = 40m/2.02s

Vix = 19.8m/s

1. If airbags reduce the impact force from an accident why has there been questions over their safety?

2. Are airbags the safest option to prevent serious injury or death from a car accident?

Answers

Answer:Air bags can leave you in even more injury, From the impact they give

You could end up with a broken nose,arm

concussion

You are a member of an alpine rescue team and must get a box of supplies, with mass 3 kg , up an incline of constant slope angle 30.0, so that it reaches a stranded skier who is a vertical distance 4 m above the bottom of the incline. There is some friction present; the kinetic coefficient of friction is 0.05. Since you can't walk up the incline, you give the box a push that gives it an initial velocity; then the box slides up the incline, slowing down under the forces of friction and gravity. Take acceleration due to gravity to be 9.81 m/s2 .What is the minimum speed v that you must give the box at the bottom of the incline so that it will reach the skier

Answers

Answer:

v = 9.04 m / s

Explanation:

For this exercise we can use the relation that the work of the non-conservative force (friction) is equal to the variation of the mechanical energy of the system.

          W = Em_f - Em₀         (1)

Starting point. Lower slope

        Em₀ = K = ½ m v²

highest point. Where is the skier at a height h

        Em_f = U = m g h

The work of rubbing

        W = -fr x

the negative sign is because the friction force opposes the movement.

Let's set a reference system where the x axis is parallel to the slope and the y axis is perpendicular

let's use trigonometry to break down the weight

        cos θ = W_y / W

        sin θ = Wₓ / W

        W_y = W cos θ

        Wₓ = W sin θ

Y axis

        N - Wₓ = 0

        N = mg sin  θ

X axis

         fr = m a

the friction force has the expression

         fr = μ N

         fr = μ mg sin θ

we look for the job

         W = - μ mg sin θ  x

where x is the distance along the slope

       

we substitute in 1

         -μ mg sin θ x = mg h - ½ m v²

let's use trigonometry to find the distance x

        tan 30 = h / x

        x = h / tan 30

we substitute

          -   [tex]\mu \ mg \ sin \theta \ \frac{h}{tan 30} \ x[/tex] = m gh - ½ m v²

we use  

          tan 30 = sin30 / cos30

         

          v² = 2g h + 2 μ g h cos 30

          v = [tex]\sqrt{ 2gh \ (1+ cos 30}[/tex]

let's calculate

          v = [tex]\sqrt{ 2 \ 9.8 \ 4 \ (1 + 0.05 \ cos \ 30)}[/tex]

          v = 9.04 m / s

A mountain climber, in the process of crossing between two cliffs by a rope, pauses to rest. She weighs 520 N. As the drawing shows, she is closer to the left cliff than to the right cliff, with the result that the tensions in the left and right sides of the rope are not the same. Find the tensions in the rope to the left and to the right of the mountain climber.

Answers

Answer:

The answer is "892.90 N"

Explanation:

Following are the solution to these question:

Calculating the vertical force of the summation that is equal to zero:

[tex]\to TL \cos 65 + TR \cos 80 -520 = 0\\\\\to 0.4226\ TL + 0.1736\ TR = 520\\[/tex]

Calculating the sum of horizontal forces that is equal to zero:

[tex]\to TL\sin 65 - TR \sin 80 = 0 \\\\\to 0.9063TL - 0.9846TR = 0\\\\\to TL = (\frac{0.9846}{0.9063})\ TR \ \ = 1.0866\ TR\\\\\to 0.4226(1.0866) \ TR +0.1736\ TR =520 \ N\\\\\to 0.6328 \ TR = 520 \\\\\to TR = 821.74 \ N \\\\\to TL = 1.0866 \times 821.74 = 892.90\ N[/tex]

Please help !!!!!!!!!!!!!!!

Answers

Answer:

9v

Explanation:

SCIENCE
The growth of algae in ocean water is limited by their need for
a.
warm ocean currents.
b.
carbon dioxide and sunlight.
c.
dissolved oxygen.
d.
low salinity.

Answers

Answer:

c is trueeeeeeeeeeeeeee

The growth of algae in ocean water is limited by their need for dissolved oxygen. Thus, the correct answer is option C.

What is algae?

The term "algae" refers to a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping of species from several distinct clades. Most are aquatic and autotrophic, lacking many of the distinct cell and tissue types found in land plants, such as stomata, xylem, and phloem.

Algae, like all organisms, normally grow in balance with their ecosystems, with the amount of nutrients in the water limiting their growth. Deep ocean water contains fewer algae because algae require sunlight and carbon dioxide to thrive.

Therefore, due to need for dissolved oxygen the growth of algae in ocean water is limited.

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Anyone know how to do this???

Answers

Answer:

World War 1 was caused by entangled alliances, nationalism, imperialism, and major

advancements in military technology. Does the Treaty of Versaille address those issues?

Explain your answer using facts. (5 points)

26. Which member of the carbon family is a non-metal?

Please help

Answers

Explanation:

Check out the Periodic Table attached here. The Carbon family is the vertical group starting with Carbon, Group 14. Nonmetals are in green, which element there is a nonmetal?

A bus is moving at a speed of 150km/hr. Begins to slow at a constant rate of 3.0m/s each second. Find how far it goes before stopping

Answers

Answer:

Distance = 13.9 meters

Explanation:

Given the following data;

Maximum speed = 150 km/hr to meters per seconds = 150 * 1000/3600 = 41.67 m/s

Decelerating speed = 3m/s

To find the distance travelled with this speed;

Distance = maximum speed/decelerating speed

Distance = 41.67/3

Distance = 13.9 meters

Therefore, the bus would travel a distance of 13.9 meters before stopping.

Please help me!!!!!!!!!

Answers

Hi there! :)

[tex]\large\boxed{17.32 m/s}[/tex]

Use the following equation in solving for kinetic energy:

KE = 1/2mv² where:

KE = kinetic energy (J)

m = mass (kg)

v = velocity (m/s)

Plug in the given values:

12,000 = 40v²

Divide both sides by 40:

12,000 / 40 = v²

300 = v²

Take the square root of both sides:

√300 = v

v ≈ 17.32 m/s

I need help please .

Answers

Answer:

option 5

Explanation:

because all u do is have to add them up

HELP ITS DUE IN 4 MINUTES

Answers

Answer:

igneous = melted rocks formed by cooled magma

sedimentary is brken rocks, kayers with fossil...

metamophic is rocks formed by pressure and heat

2.3 The motion of an object is accelerated
when its speed:
a
decreases
b remains constant
increases.​

Answers

Answer:

The motion of an object is accelerated when its speed increases.

please someone help me !!

Answers

Answer:

D

Explanation:

because if the solvent is more than the solvent then we can't resolve it.

so our product will be suspended

When the temperature of a certain solid, rectangular object increases by AT, the length of one
side of the object increases by 0.010% = 1.0 x 10-4 of the original length. The increase in volume
of the object due to this temperature increase is​

Answers

Explanation:

iausiaolalalLosjjskskakOaokasksoososoapapozosiosoa

Two type of microscopes used to view cells are optical and__ microscopes
options:

laser
Electron

Answers

I believe the answer is Electron

three small balls each of mass 13.3g are suspended separately from a common point by silk threads, each 1.17m long. The balls are identically charged hang at the corners of equilateral triangle 15.3 cm on a side. Find the charge on each ball

Answers

The balls are identical charges hang at the corners of equlilateral

The charge on each ball is 6.1 ×10⁻⁸ C.

What is force?

The definition of force in physics is: The push or pull on a massed object changes its velocity.

An external force is an agent that has the power to alter the resting or moving condition of a body. It has a direction and a magnitude. A spring balance can be used to calculate the Force. The Newton is the SI unit of force.  Force is a vector quantity and it has both magnitude and direction.

Let the balls have equal charge of q. Then, electrostatic force acting on each particle = √3 q²/r² dyne =  √3 q²/15² dyne =0.0076 q².

Weight of each ball = 13.3 ×980 dyne = 13034 dyne.

As the electrostatic force and the weight acts perpendicular to each other.

Hence, 0.1/√3 = 0.0076 q²/13034

q = 6.1 ×10⁻⁸ C

Hence, the charge on each ball is  6.1 ×10⁻⁸ C.

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A train crosses 650m long bridge and 800m long platform in 20sec and 30 sec respectively. what is speed of train?​

Answers

Answer:

29 m/s

Explanation:

Assuming the bridge and the platform are back to back,

Average speed = Total Distance/ Total Time

Avg S = 1,450m/50s = 29 m/s

The average speed of the train is 29 m/s

The average speed is defined as the ratio of total distance traveled and the total time taken.

    Total distance = 650 m + 800 m = 1450 m

     Total Time      = 20 s + 30 s = 50 s

    Average speed = total distance/total time

                               = 1450 / 50

                               = 29 m/s is the average speed of the train.

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Plaskett's binary system consists of two stars that revolve in a circular orbit about a center of mass midway between them. This statement implies that the masses of the two stars are equal (see figure below). Assume the orbital speed of each star is |v with arrow| = 230 km/s and the orbital period of each is 15.5 days. Find the mass M of each star. (For comparison, the mass of our Sun is 1.99 1030 kg.)

Answers

Answer:

[tex]1.554\times 10^{32}\ \text{kg}[/tex]

Explanation:

M = Mass of each star

T = Time period = 15.5 days

v = Orbital velocity = 230 km/s

G = Gravitational constant = [tex]6.674\times 10^{-11}\ \text{Nm}^2/\text{kg}^2[/tex]

Radius of orbit is given by

[tex]R=\dfrac{vT}{2\pi}[/tex]

We have the relation

[tex]\dfrac{Mv^2}{R}=\dfrac{GM^2}{(2R)^2}\\\Rightarrow M=\dfrac{4Rv^2}{G}\\\Rightarrow M=\dfrac{4\dfrac{vT}{2\pi}v^2}{G}\\\Rightarrow M=\dfrac{2v^3T}{\pi G}\\\Rightarrow M=\dfrac{2\times 230000^3\times 15.5\times 24\times 60\times 60}{\pi\times 6.674\times 10^{-11}}\\\Rightarrow M=1.554\times 10^{32}\ \text{kg}[/tex]

The mass of each star is [tex]1.554\times 10^{32}\ \text{kg}[/tex]

When scientists use one of their five senses to gather information, they are
A.
drawing a conclusion.
B.
making an inference.
C.
predicting a relationship
D.
making an observation.

Answers

D. Making an observation.

Answer:

making an observation

Explanation:

What is the force of gravity between two 40.0kg masses that are separated by 3.00m?

Answers

Answer:

[tex]f = g \times \frac{m1 \times m2}{ {d}^{2} } [/tex]

[tex]f = 6.67 \times {10}^{ - 11} \times \frac{40 \times 40}{9} [/tex]

F=1.2x 10^-8

1. Describe the components of the reflex arc

Answers

The simplest arrangement of a reflex arc consists of the receptor, an interneuron (or adjustor), and an effector; together, these units form a functional group. Sensory cells carry input from the receptor (afferent impulses) to a central interneuron, which makes contact with a motor neuron.
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Serafina and the Black Cloak is full of figurative language. For this assignment, you will be locating five examples of figurative language from anywhere in the book that you have read. 1. You must write type out the exact example in quotation marks and give the page number.2. You must tell what type of figurative language it is. Use the anchor chart in the module to help you remember which is which.3. You must also explain what the figurative language is telling or explaining. Mrs. Torres is mailing a package that weighs 4.5 pounds. The post office charges by the ounce to mail a package. How much does the package weigh in ounces? Which is an example of a SMART goal that values improvement on Fitness Gram?AI will decrease my one mile run time from 10 minutes to 2 minutes in 3 weeks.B.I will run faster on the pacer next time.I will increase my number of push-ups by 10 at the nine-week benchmark.DI will lose 20 pounds in 6 weeks. Please help ASAP please and thank you have a great and blessed day! In 2020, Bertha Jarow had a $28,000 loss from the sale of a personal residence. She also purchased from an individual inventor for $7,000 (and resold in two months for $18,000) a patent on a rubber bonding process. The patent had not yet been reduced to practice. Bertha purchased the patent as an investment. In addition, she had the following capital gains and losses from stock transactions: Long-term capital loss ($6,000) Long-term capital loss carryover from 2019 (12,000) Short-term capital gain 21,000 Short-term capital loss (7,000)A. Bertha has a net long-term capital loss of $___. Bertha has a net short-term capital gain of $ 14000. As a result, Bertha has an overall net short-term capital gain of $___.B. Complete the letter to Bertha explaining the tax treatment of the sale of her personal residence. Assume Bertha's income from other sources puts her in the 28% bracket. Blank minus 1/10 equals 1/2 18(3x+1)+3 ; x=2 evaluate the expression for the given value of the variable. Which letter represents theSouth American Plate I'm in a test please help Select ALL the correct answers. A bicycle manufacturer uses the given expression to model the monthly profit from sales of a new model of bicycle, where x is the selling price of one bicycle, in dollars. -12 + 3001 20,000 At what selling prices for the bicycle will the manufacturer make neither a profit nor a loss? $50 $250 $200 $100 $150 $300 Come up with five ethical guidelines for research. Write statements that reflect your own views ofwhat is right and wrong. If you really love animals, an example of one guideline might be "Noanimals may be used in research of any kind." However, when coming up with these guidelines, bethoughtful about what they really mean. Think of the information you read about earlier. Try tophrase your guidelines in a way that would allow research that you think would be beneficial tostill be done. You may find that certain circumstances may cause you to rethink your own ethics! Imagine that you ask your dad to fix your car, and after a few minutes, herealizes that the problem is minor. What does he say?O A. Ce n'est rien.O B. J'en ai marre.C. Je n'ai pas le temps.D. Je fais de mon mieux. Which body in our solar system has the most Gravity? complete the table. percent discount 25% sale price $40whats the og price wah wah wah wah wah? (what is the GCF of 100 and 200?) GIVING BRAINLIEST AND THE REST OF MY POINTS!!!!How are a tundra and a desert different?A) A tundra has a lot of precipitation and a desert has little.B) A tundra has few trees and plants and deserts have many.C) A tundra has soil that is often sandy and a desert has grass.D) A tundra is dry and cold and a desert is dry and hot. aiko is biulding a tower out of paper she starts by making 2 congruent circular bases she then makes 1 curved surface sor the body of the tower what 3 dimensional figure does aiko biuld HELP!!!!!!! if link will report!! I am timed Please help!!! The process by which weak nuclear forces in carbon-14 isotopes transform a neutron into a patron an electron is called wht find the lateral surface area of the prism below PLS ANWSER QUIC Need help ASAP QUESTION 13