A construction laborer holds a 20 kg sheet of wallboard 3 m above the floor for 4 seconds. During these 4 seconds how much power was expended on the wallboard

Answers

Answer 1

Answer:

zero

Explanation:

no distance has moved while holding the sheet...so no distance means no workdone..no workdone means no power...


Related Questions

use particle motion to explain what happens when molten steel becomes a steel beam to be used in construction. ​

Answers

Explanation:

A molten steel is in a liquid phase of matter. It has no defined volume of shape at this state. The particles inside this materials in this form is randomized by they are still attached to each other.

On cooling, when the molten steel solidifies and sets into a solid steel beam, the particles take up a fixed position and forms a definite shape and this confers a definite volume on them. The randomized particles stops and forms fixed crystals about their lattice. This way, the beam can carry and support a fixed amount of load.

A local FM radio station broadcasts at a frequency of 97.3 MHz. Calculate the energy of the frequency at which they are broadcasting. Energy

Answers

Answer:

6.45×10¯²⁶ J

Explanation:

From the question given above, the following data were obtained:

Frequency (f) = 97.3 MHz

Energy (E) =?

Next, we shall convert 97.3 MHz to Hz. This can be obtained as follow:

1 MHz = 1×10⁶ Hz

Therefore,

97.3 MHz = 97.3 MHz × 1×10⁶ Hz / 1 MHz

97.3 MHz = 9.73×10⁷ Hz

Thus, 97.3 MHz is equivalent to 9.73×10⁷ Hz.

Finally, we shall determine the energy at which the frequency is broadcasting. This can be obtained as follow:

Frequency (f) = 9.73×10⁷ Hz

Planck's constant (h) = 6.63×10¯³⁴ Js

Energy (E) =?

E = hf

E = 6.63×10¯³⁴ × 9.73×10⁷

E = 6.45×10¯²⁶ J

Therefore, the energy at which the frequency is broadcasting is 6.45×10¯²⁶ J

EX 6-1 A ball is twirled on a 0.870 - m-long string with a constant speed of 3.36 m / s . Calculate the acceleration of the ball. Be sure to specify the direction of the acceleration.

Answers

Answer:

[tex]a=12.97\ m/s^2[/tex]

Explanation:

Given that,

The length of a string, l = 0.87 m

Speed of the ball, v = 3.36 m/s

We need to find the acceleration of the ball. The acceleration acting on the ball is centripetal acceleration. It is given by :

[tex]a=\dfrac{v^2}{r}\\\\a=\dfrac{(3.36)^2}{0.87}\\\\=12.97\ m/s^2[/tex]

So, the acceleration of the ball is [tex]12.97\ m/s^2[/tex].

An automobile which set the world record for acceleration increase speed from rest to 96 km/h in 3.07 seconds what distance traveled by the time the final speed was achieved

Answers

Answer:

41.02m

Explanation:

Given parameters:

Initial velocity = 0m/s

Final velocity  = 96km/hr

Time taken  = 3.07s

Unknown:

Distance traveled by the time the final speed was achieved = ?

Solution:

To solve this problem, we first find the acceleration of the car;

     Acceleration  = [tex]\frac{v - u }{t}[/tex]

v is the final velocity

u is the initial velocity

t is the time taken

  Now convert the the final velocity to m/s;

          96km/hr to m/s;

               1 km/hr  = 0.278m/s

               96km/hr  = 96 x 0.278 = 26.7m/s

Now;

 Acceleration  = [tex]\frac{26.7 - 0}{3.07}[/tex]   = 8.69m/s²

So;

   v²  = u²  + 2as

v is the final velocity

u is the initial velocity

a is the acceleration

s is the distance

             26.7²  = 0²  + 2 x 8.69 x s

             712.89  = 17.38s

                  s  = 41.02m

which sun's energy comes from which nuclear reaction​

Answers

Answer:

the nuclear fusion process

Explanation:

:)

Answer:

nuclear fusion (not fission)

Explanation:

a p e x :))

what is the electrical potential at the surface of gold nucleus? The radius of a gold atom is 6.6*10​

Answers

Complete question is;

What is the electrical potential at the surface of gold nucleus? The radius of a gold atom is 6.6 × 10​^(-5) m and atomic number z = 79.

Answer:

172.36 × 10^(-5) V

Explanation:

We are given;

Radius; r = 6.6 × 10^(-5) m

Atomic number; Z = 79

Formula for Electric potential here is;

V = kZe/r

Where;

e is charge on proton = 1.6 × 10^(-19) C

k has a constant value of 9 × 10^(9) N⋅m²/C²,

​Thus;

V = (79 × 1.6 × 10^(-19) × 9 × 10^(9))/(6.6 × 10^(-5))

V = 172.36 × 10^(-5) V

Sketch the electric field around these two objects if they have the same sign of charge. Make a separate drawing showing equipotential lines around the two charges. The potential is defined to be zero at infinity. Identify the line of zero potential between the two charges, if there is one.

Answers

Answer:

* far from one of the charges, the field of the other charge is small and can be neglected

* on the outside of the loads the fields are added territorially

* between the charges the two fields tend to vanish

Explanation:

The electric field around two objects with charge of the same sign, for simplicity suppose that the objects have positive point spherical charges,

          E = k q / r2

bold letters indicate vectors, therefore the total electric field is

           E_total = E1 + E2

the module of this field is

           E_total = E1- E2

therefore we can outline this field

* far from one of the charges, the field of the other charge is small and can be neglected

* on the outside of the loads the fields are added territorially

* between the charges the two fields tend to vanish

An outline of these shows in Attachment A

The equipotential surfaces are defined as being perpendicular to the electric field lines since the electric field and the power difference are related

              E = [tex]\frac{dV}{dx} i^ + \frac{dV}{dy} j^ + \frac{dV}{dz} k^ = \Delta V[/tex]

We can schematize some characteristics of these surfaces

* very close to each load are spherical surfaces

* very far from the load is an elliptical surface, which envelops the loads

* between them there is a point of zero potential point C

See attached part B

The masses of the two moons are determined to be 2M2M for Moon AA and MM for Moon BB . It is observed that the distance between Moon BB and the planet is two times that of the distance between Moon AA and the planet. How does force exerted from the planet on Moon AA compare to the force exerted from the planet on Moon BB

Answers

Answer:

 F_A = 8 F_B

Explanation:

The force exerted by the planet on each moon is given by the law of universal gravitation

        F = [tex]G \frac{m M}{r^{2} }[/tex]

where M is the mass of the planet, m the mass of the moon and r the distance between its centers

let's apply this equation to our case

Moon A

the distance between the planet and the moon A is r and the mass of the moon is 2m

        F_A = G \frac{2m M}{r^{2} }

Moon B

        F_B = G \frac{m M}{(2r)^{2} }

         F_B = G \frac{m M}{4 r^{2} }

the relationship between these forces is

         F_B / F_A = [tex]\frac{1}{2 \ 4 }[/tex] = 1/8

         F_A = 8 F_B

Answer:

F_A = 8 F_B

Explanation:

The force exerted by the planet on each moon is given by the law of universal gravitation

       F =

where M is the mass of the planet, m the mass of the moon and r the distance between its centers

let's apply this equation to our case

Moon A

the distance between the planet and the moon A is r and the mass of the moon is 2m

       F_A = G \frac{2m M}{r^{2} }

Moon B

       F_B = G \frac{m M}{(2r)^{2} }

        F_B = G \frac{m M}{4 r^{2} }

the relationship between these forces is

        F_B / F_A =  = 1/8

        F_A = 8 F_B

Marvin the Martian needs to get back home. Marvin is 321,770 m from his home on Mars. He decides the quickest way to get home is to use his canon to fire himself into flight. He aims the the canon at an angle of 25 degrees. When the canon is fired Marvin the Martian is launched into flight at an initial velocity of 1250 m/s. The question is will his plan work

Answers

Answer:

y = 14238 m.    the height of the rocket is much less than this distance therefore the plan will not work.

Explanation:

Let's analyze this exercise, so that the Martian's plan works, the vertical height of the body must be zero when it is more than half of the way to the planet Mars, this is so that Mars attracts it and can arrive.

Let's calculate the maximum height of the launch

          [tex]v_{y} ^2 = v_{oy}^2 - 2 g y[/tex]

at the highest point [tex]v_{y}[/tex] = 0

          y = v_{oy}² / 2g

          y = (v₀ sin θ)² / 2g

let's calculate

          y = (1250 sin 25)² /2 9.8

          y = 14238 m

In the exercise, indicate that the distance to Mars is h = 321770 m, half of this distance is

          h / 2 = 160885 m

therefore the height of the rocket is much less than this distance therefore the plan will not work.

The height reached is low, so it is not necessary to take into account the variation of g with height

Use the graph and the table above to complete the table by estimating the amount of energy transferred near location B.

A.
1600 kilojoules

B.
300 kilojoules

C.
800 kilojoules

D.
400 kilojoules

E.
3200 kilojoules

Answers

Answer:

A. 1600 kilojoules

Explanation:

Looking at the graph, at 4 meters, we can guess the energy transferred would be around 1500 kilojoules. 1600 kilojoules is the closest to that value, so A would be the best choice.

Using a pulley, you apply a force of 10 Newtons to life an object that weighs 100 Newtons. What is the mechanical advantage of that pulley?

Answers

Answer: 10

Explanation:

The mechanical advantage of that pulley is 10.

What is mechanical advantage?

The force amplified by utilizing a tool, mechanical device, or machine system is known as mechanical advantage. To achieve the desired output force amplification, the gadget trades off input forces against movement. The law of the lever serves as a paradigm for this.

Mechanisms are machine parts made to control forces and motion in this way.

Given that: the weighs of the object: W = 100 Newton.

Applied force: F = 10 N.

For using a pulley, you have to apply a force of 10 Newtons to lift  an object that weighs 100 Newtons.

Hence, the mechanical advantage of the pulley is

= Weighs of the object/applied force

= 100 Newton / 10 Newton.

= 10.

The mechanical advantage of it is 10.

Learn more about mechanical advantage here:

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A man drops a ball off of a 7.2 m high cliff, what is the ball's velocity as it hits the ground?
(- 12m/s)
Proof llease

Answers

Answer:

19.3 m/s

Explanation:

Take down to be positive.  Given:

Δy = 19 m

v₀ = 0 m/s

a = 9.8 m/s²

Find: v

v² = v₀² + 2aΔy

v² = (0 m/s)² + 2 (9.8 m/s²) (19 m)

v = 19.3 m/s

My camera quality is bad. Sorry..

A rectangular block weighs 240 N. the area of the block in contact with the floor is 20 cm2.calculate the pressure on the floor(give your answer in N/cm2
Help me Fast as you can,,

Answers

Answer:

12 N/cm²

Explanation:

From the question given above, the following data were obtained:

Weight (W) of block = 240 N

Area (A) = 20 cm²

Pressure (P) =?

Next, we shall determine the force exerted by the block. This can be obtained as follow:

Weight (W) of block = 240 N

Force (F) =.?

Weight and force has the same unit of measurement. Thus, we force applied is equivalent to the weight of the block. Thus,

Force (F) = Weight (W) of block = 240 N

Force (F) = 240 N

Finally, we shall determine the pressure on the floor as follow:

Force (F) = 240 N

Area (A) = 20 cm²

Pressure (P) =?

P = F/A

P = 240 / 20

P = 12 N/cm²

Therefore, the pressure on the floor is 12 N/cm².

A2 kg object moves at a constant 5 m/s across a level surface. Determine its kinetic energy.

Answers

KE = 1/2mv^2
KE= 1/2(2)(5)^2
KE= 25 J

The least count of stopwatch is 0.2s.The time of 20 oscillations of a pendulum was measured to be 25s.Find the percentage error in the measurement of time​

Answers

Answer:

0.8%

Explanation:

We are given;

Number of oscillations; n = 20

Time taken; t = 25 s

Formula for period of oscillation;

T = t/n = 25/20 = 1.25 s

We are told that the least count is 0.2 s. Thus, error is; ΔT = 0.2 s

percentage error in the measurement of time is given by;

(0.2/(20 × 1.25)) × 100% = 0.8%

Two identical plastic cups contain the same amount of water at two different temperatures, as shown to the left. Both cups are placed in a room at 25° Celsius. At the time cups were placed in the room, in which cup do the water molecules have higher average kinetic energy? ( Cup 1 © Cup 2​

Answers

Answer:

the molecules will begin to move slowly and will turn to ice

Explanation:

hope this was good or not not sure if am right but yeah

23. What mass of water will give up 240 calories
when its temperature drops from 80°C to 68°C?

Answers

Answer:

20g

Explanation:

Given parameters:

Quantity of heat  = 240calories

Initial temperature  = 80°C

Final temperature  = 68°C

Unknown:

Mass of water = ?

Solution;

To solve this problem, we use the expression:

         Q  = m c (t₂  - t₁)

Q is the quantity of heat

m is the mass

c is the specific heat = 1 cal/g°C

t₂ is the final temperature

t₁ is the initial temperature

  Insert the parameters and solve;

  Change in temperature is an absolute value

          240 = m x 1 x (68 - 80)

           m  = 20g

How will a metal container full of hot water in vaccum lose heat?​

Answers

Hey I hope you had some fun with me I love y’all so I’m gonna have a great time with your friends and I love y’all too babe I hope you have some great time love y’all babe I hope you have some great time love y’all love love?

During the study of the objects,What we can observe​

Answers

There is no picture attached?

You throw a baseball straight up in the air with an initial velocity of 41 m/s What is the maximum height the baseball reaches above your hand?

Answers

Answer:

85.77 m

Explanation:

From the question given above, the following data were obtained:

Initial velocity (u) = 41 m/s

Final velocity (v) = 0 m/s (at maximum height)

Acceleration due to gravity (g) = 9.8 m/s²

Maximum height (h) =?

The maximum height reached by the ball can be obtained as follow:

v² = u² – 2gh (since the ball is going against gravity)

0² = 41² – (2 × 9.8 × h)

0 = 1681 – 19.6h

Collect like terms

0 – 1681 = –19.6h

–1681 = –19.6h

Divide both side by –19.6

h = –1681 / –19.6

h = 85.77 m

Thus, the maximum height reached by the ball is 85.77 m

A football player kicks a ball with a mass of 0.5 kg. The average acceleration of the football was 15 m/s/s. How much force did the kicker apply to the football?

Answers

Answer:

i think its 8.2

Explanation:

A concave lens can be used to produce an enlarged and erect image. True or False?​

Answers

Answer:

False

Explanation:

A single concave lens has the opposite effect of a magnifying glass.

The given statement is false. A concave lens can only form an erect, diminished and virtual image of an object.

WILL GIVE BRAINLIEST TO THE CORRECT ANSWER
PLEASE HELP THIS IS DUE TODAY!

If a 1000kg car is accelerating at 3m/s/s for 4 seconds how far will it travel

Answers

12 meters, brainly won’t let me submit it keeps saying incorrect answer

Which of the following is NOT a possible type of law that a government could pass to help fight climate change?
1. Making greenhouses gas production illegal
2. Regulating the amount of greenhouse gases businesses can produce
3. Funding research on technologies that are better for the environment than those we currently use
4. Providing tax incentives for businesses and people to take action

Answers

Answer:

4

Explanation:

because people could lie about it

5. What is the area of space around a magnet called?
O Magnetic field
O Magnetic space
O Induced magnet


ILL MARK BRAINLYEST PLZ HELPPPP HURRY !!!!!!!!!!!!!!!!!!!!!!!!

Answers

Answer:

Magnetic Field

Explanation:

Answer:

Magnetic field

Explanation:

A 420 g soccer ball is kicked into the air with an initial velocity of 30 m/s. How much kinetic energy does the soccer ball have?

Answers

Answer:189000J

Explanation:KE=1/2mv^2

1/2(420g)(30m/s)^2

=189000J

Answer right I will cashapp $5

Someone made a copy of an analog wave and a digital wave. Compare the copies
with the original waves. Then, explain which type of wave is a more reliable way to
encode and transmit information.

Answers

Analog transfer information quicker, example electromagnetic waves which are used in our modern day phones.

Answer:

The original analog sound waves are perfect but the copy is not because most analog waves have wavelengths that are too long to reproduce in copies

The original digital waves and the copy are perfect because with digital waves no information gets lost in the transfer of data, and there is no additional noise added to the copy.

Analog refers to audio recorded using methods that replicate the original sound waves. Digital audio is recorded by taking samples of the original sound wave at a specified rate.

Explanation:

i dont need $5

i wrote this using information from go ogle and some from brai nly. I hope it helps.

what medical uses does radiation have?​

Answers

Answer:

Radiation is used in monitoring the response of tumors to treatment and in distinguishing malignant tumors from benign ones. Bone and liver scans can detect cancers that have spread to these organs. Half of all people with cancer are treated with radiation, and the number of those who have been cured continues to rise.

Explanation:

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A 55.0 kg student feels a
2.68 x 10-8 N gravitational force
from a Physics book 0.435 m away.
What is the mass of the Physics
book?

Answers

Mass of book will be m = 4.495 kg  

What is gravitational force ?

The force of attraction between all masses in the universe; especially the attraction of the earth's mass for bodies near its surface is called gravitational force

Force = 2.68 x 10-8 N

mass of student(M)  = 55

mass of book=?

distance = 0.435m

gravitational constant (G)=6.67×10^-11

gravitational force (F)=2.68×10^-8

gravitational force (F) = (G*M*m) /[tex]d^{2}[/tex]

2.68 x 10-8  = ((6.67×10^-11) * ( 55 ) * m) / 0.435

m = 4.495 kg

Mass of book will be m = 4.495 kg  

learn more about gravitational force  

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Answer:

acellus students

Explanation

1.382

Delaney loves her new kiddie pool, but she is afraid to get wet. She crawls around the outside of the pool for hours. Jocelyn says Delaney is making rotations around the pool and Jonathan says Delaney is making revolutions around the pool. Who is correct? Suppose your answer with evidence.

Answers

Answer:

Revolutions

Explanation:

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