10. A 90 kg box is sliding across a surface at a constant velocity while experiencing a rightward applied
force of 40 N. Calculate the force of friction acting on the box.
A. -40N
B. +40N
C.-2.5 N
D. 0 N

Answer:

nearly 2 days or less hes fast but not that fast

Explanation:

but maybe he can run it in five minutes

Answer:

clockwise

Explanation:

According to the law given by Lenz, known as the Lenz law, it is said that a current induced in the circuit which is due to the change in the magnetic field and is so directed so as to oppose the change in the flux and to apply a force in the opposite direction if the force.

Here, as the magnetic field is directed out of the screen, the current flows in the direction which is clockwise in the loop and it opposes the increasing magnetic field.

The clockwise induced current will produce magnetic field in to the screen.

Answer:

B

Explanation:

I'm learning it in science.

Answer:

its not b i just took the test and b was wrong

Explanation:

A ripcord system pulls a closing pin, which releases a spring-loaded pilot chute, and opens the container; from which the parachute comes out.

If a skydiver is unable to open her/his parachute, an automatic activation device will automatically open the parachute.

A parachute works by forcing air into the front of it and creating a structured 'wing' under which the canopy pilot can fly. Parachutes are controlled by pulling down on steering lines which change the shape of the wing, cause it to turn, or to increase or decrease its rate of descent.

"Radiocarbon dating is a method for determining the age of an object containing organic material by using the properties of radiocarbon."

Answer:

well for me I think

Explanation:

The use of carbon 12 to tell the age of substances

Answer:

(2x + 4)(x - 4)=2x^2-4x-16

Answer:

v0 = 24.42 m/s (Approx)

Explanation:

Given:

Increase in frequency = 7.1% =

Computation:

Assume n = 100%

n1 = [(v+v0)/(v+v1)]n

[100 + 7.1] =  [(344+v0)/(344+0)]100

107.1 =   [(344+v0)/(344)]100

v0 = 24.42 m/s (Approx)

Answer:

66.475kJ

Explanation:

Work done is the product of the force and perpendicular distance in direction of the force.

Work done = Force × distance

Given

Weight = 700lb

Distance = 70ft

1lb force = 4.448N

700lb force = 700(4.448) = 3113.6N

Distance = 70(0.305) = 21.35m

Work done = 3113.6×21.35

Work done ≈ 66,475Joules

Work done = 66.475kJ

Answer:

[tex]5.33\ m/s[/tex]

Explanation:

[tex]We\ know\ that,\\Momentum=Mass*Velocity\\p=mv\\Hence,\\Lets\ first\ consider\ the\ case\ of\ the\ two\ balls\ 'Before\ Collision':\\\\Mass\ of\ the\ green\ ball=0.2\ kg\\Initial\ Velocity\ of\ the\ green\ ball=5\ m/s\\Initial\ Momentum\ of\ the\ green\ ball=5*0.2=1\ kg\ m/s\\\\Mass\ of\ the\ pink\ ball=0.3\ kg\\Initial\ Velocity\ of\ the\ pink\ ball=2\ m/s\\Initial\ Momentum\ of\ the\ pink\ ball=0.3*2=0.6\ kg\ m/s\\\\Total\ momentum\ of\ both\ the\ balls\ 'Before\ Collision'=1+0.6=1.6\ kg\ m/s[/tex]

[tex]Hence,\\Lets\ now\ consider\ the\ case\ of\ the\ two\ balls\ 'After\ Collision':\\\\Mass\ of\ the\ green\ ball=0.2\ kg\\Final\ Velocity\ of\ the\ green\ ball=0\ m/s\\Final\ Momentum\ of\ the\ green\ ball=0\ kg\ m/s\\\\Mass\ of\ the\ pink\ ball=0.3\ kg\\Final\ Velocity\ of\ the\ pink\ ball=v\ m/s\\Final\ Momentum\ of\ the\ pink\ ball=0.3*v=0.3v\ kg\ m/s\\\\Total\ momentum\ of\ both\ the\ balls\ 'After\ Collision'=0+0.3v=0.3v\ kg\ m/s[/tex]

[tex]As\ we\ know\ that,\\Through\ the\ law\ of\ conservation\ of\ momentum,\\In\ an\ isolated\ system:\\Total\ Momentum\ Before\ Collision=Total\ Momentum\ After\ Collision\\Hence,\\1.6=0.3v\\v=\frac{1.6}{0.3}=5.33\ m/s[/tex]

Answer:

yes

Explanation:

Answer:

Explanation:

The average kinetic energy can be found by using the formula

[tex]k = \frac{1}{2} m {v}^{2} \\ [/tex]

m is the mass

v is the velocity

From the question we have

[tex]k = \frac{1}{2} \times 200 \times {5}^{2} \\ = 100 \times 25[/tex]

We have the final answer is

Hope this helps you

Answer:

Explanation: The chemical action that occurs in the cell while the current is flowing causes hydrogen bubbles to form on the surface of the anode. This action is called POLARIZATION. Some hydrogen bubbles rise to the surface of the electrolyte and escape into the air, some remain on the surface of the anode. If enough bubbles remain around the anode, the bubbles form a barrier that increases internal resistance. When the internal resistance of the cell increases, the output current is decreased and the voltage of the cell also decreases.

   A cell that is heavily polarized has no useful output. There are several methods to prevent polarization or to depolarize the cell.

   One method uses a vent on the cell to permit the hydrogen to escape into the air. A disadvantage of this method is that hydrogen is not available to reform into the electrolyte during recharging. This problem is solved by adding water to the electrolyte, such as in an automobile battery. A second method is to use material that is rich in oxygen, such as manganese dioxide, which supplies free oxygen to combine with the hydrogen and form water.

   A third method is to use a material that will absorb the hydrogen, such as calcium. The calcium releases hydrogen during the charging process. All three methods remove enough hydrogen so that the cell is practically free from polarization.

LOCAL ACTION

   When the external circuit is removed, the current ceases to flow, and, theoretically, all chemical action within the cell stops. However, commercial zinc contains many impurities, such as iron, carbon, lead, and arsenic. These impurities form many small electrical cells within the zinc electrode in which current flows between the zinc and its impurities. Thus, the chemical action continues even though the cell itself is not connected to a load.

   Local action may be prevented by using pure zinc (which is not practical), by coating the zinc with mercury, or by adding a small percentage of mercury to the zinc during the manufacturing process. The treatment of the zinc with mercury is called amalgamating (mixing) the zinc. Since mercury is many times heavier than an equal volume of water, small particles of impurities weighing less than mercury will float to the surface of the mercury. The removal of these impurities from the zinc prevents local action. The mercury is not readily acted upon by the acid. When the cell is delivering current to a load, the mercury continues to act on the impurities in the zinc. This causes the impurities to leave the surface of the zinc electrode and float to the surface of the mercury. This process greatly increases the storage life of the cell.

Answer:

a

[tex]L = 5.25*10^{7} \ m[/tex]

b

[tex]m = 1 \ kg[/tex]

c

[tex]t = 1.46112000000 *10^{11} \ s[/tex]

Explanation:

From the question we are told that

     Length  is   L  = 52500000 m

      Mass  is    

     Time  is   2435200000    minutes

Generally the proper SI for length is  meters ,

Now converting the given length to proper SI form using the appropriate prefixes we have that

             [tex]L = 5.25*10^{7} \ m[/tex]

Generally the proper SI for mass is  kilograms

converting  grams to kilograms , we have

           [tex]m =\frac{1000}{1000 }[/tex]

=>       [tex]m = 1 \ kg[/tex]

Generally the proper SI for time  is  seconds

converting  minutes  to seconds , we have

        [tex]t = 24352000000* 60[/tex]

=>      [tex]t = 146112000000 \ s[/tex]

Now converting to the  proper SI form using the appropriate prefixes

        [tex]t = 1.46112000000 *10^{11} \ s[/tex]

Answer:

The cantaloupe has a speed of 117.6 m/s

Explanation:

Free Fall Motion

It occurs when an object falls under the sole influence of gravity. Any object that is being acted upon solely by the force of gravity is said to be in a state of free fall. Free-falling objects do not face air resistance.

If an object is dropped from rest in a free-falling motion, it falls with a constant acceleration called the acceleration of gravity, which value is [tex]g = 9.8 m/s^2[/tex].

The final velocity of a free-falling object after a time t is given by:

vf=g.t

The cantaloupe has been dropped from rest. We are required to find the speed after t=12 seconds.

Calculate the final speed:

vf=9.8 * 12 = 117.6 m/s

The cantaloupe has a speed of 117.6 m/s

Complete Question

1 a A little girl pushes a 5.0 kg toy baby stroller at constant speed 7.0 m across the floor. She pushes on the handle with a force of 40 N at an angle of 30o with the horizontal.  How much work is done by the girl on the wagon?

1b  A farmhand pushes 20 ㎏ bale of hay 4m across the floor of the barn if she exerts a horizontal force of 60 N on the hay, how much work is done? (5 pts)

All parts are 4 points each

Answer:

1a

  [tex]W = 242.5 \ J[/tex]

1b

    [tex]W = 240 \ J[/tex]

Explanation:

Considering question a

From the question we are told that

       The mass of the toy baby stroller is  [tex]m = 5.0 \ kg[/tex]

        The distance covered is    [tex]d = 7.0\ m[/tex]

          The force the girl applies on the handle  is  [tex]F = 40 \ N[/tex]

          The angle at which this force is applied is  [tex]\theta = 30^o[/tex]

Generally the workdone is mathematically represented as

          [tex]W = F_x * d[/tex]

Here  [tex]F_x[/tex] is the force along the horizontal axis , this is mathematically represented as

           [tex]F_x = F cos (\theta )[/tex]

=>         [tex]F_x = 40 * cos(30 )[/tex]

=>         [tex]F_x = 34.64 \ N[/tex]

So

              [tex]W = 34.64 * 7[/tex]

=>           [tex]W = 242.5 \ J[/tex]

Considering question b

From the question we are told that

       The mass of the toy baby stroller is  [tex]m = 20 \ kg[/tex]

        The distance covered is    [tex]d = 4 \ m[/tex]

          The force the girl applies on the handle  is  [tex]F = 60 \ N[/tex]      

Generally the workdone is mathematically represented as

          [tex]W = F * d[/tex]

=>     [tex]W = 60 * 4[/tex]

=>     [tex]W = 240 \ J[/tex]

Answer:

B. Planet X, because its line has the greater slope.

Explanation:

In a speed graph, acceleration is slope. A greater slope means a greater acceleration. According to Newton's 2nd law (F=mg), a greater acceleration means a greater force.

Planet X exerts the greater force of gravity on the sphere, because its line has the greater slope. Hence option B is correct.

Gravitational force is force of attraction between two masses. Gravitational force(F) between two bodies is directly proportion to the product of masses(m₁,m₂) of two bodies and inversely proportional to square of distance(r) between them. mathematically it is written as,

F ∝ m₁.m₂

F ∝ 1/r²

F = G m₁,m₂÷r²

where G is gravitational constant, whose value is 6.6743 × 10⁻¹¹ m³ kg-1s⁻².

Force is expressed in Newton N in SI unit. its dimensions are [M¹L¹T⁻²].

This is analogous with coulomb's law which gives force between two charges.

if a planet has greater gravitational force(force of gravity), then body falls with greater speed as compare to other planet which is having less force of gravity. we can see in case of planet X there is greater speed as compare to plane Y in short time. Hence option B is correct.

To know more about Gravity :

https://brainly.com/question/31321801

#SPJ2.

Answer:

 N= 3

Explanation:

For this exercise we must use Faraday's law

          E = - dФ / dt

         Ф = B . A = B Acos θ

tje bold indicate vectors. As it indicates that the variation of the field is linear, we can approximate the derivatives

         E = - A cos θ (B - B₀) / t

The angle enters the magnetic field and the normal to the area is zero

         cos 0 = 1

         A = π r²

In the length of the wire there are N turns each with a length L₀ = 2π r

          L = N (2π r)

          r = L / 2π N

    we substitute

          A = L² / (4π N²)

The magnetic field produced by a solenoid is

           B = μ₀ N/L   I

for which

            B₀ = μ₀  N/L   I

The final field is zero, because the current is zero

            B = 0

We substitute

           E = - (L² / 4π N²)  (0 - μ₀ N/L I) / t

           E = μ₀ L I / (4π N t)

           N = μ₀ L I / (4π t E)

The electromotive force is E = 0.80 mV = 0.8 10⁻³ V

let's calculate

           N = 4π 10⁻⁷ 200 1.60 / (4π 0.120 0.8 10⁻³)]

           N  = 320 10⁻⁷ / 9.6 10⁻⁶

           N = 33.3 10⁻¹

          N= 3

Answer:

Informal education is important because it can help individual to learn how to react and control situations.

It help individual to improve on its existing knowledge, new skills or ideas. This kind of education can happen any where and it can add values to the learner.

Explanation:

Informal education is a type of education that is learned from different life experiences, happenings outside a structured curriculum.

Informal education is important because it can help individual to learn how to react and control situations.

It help individual to improve on its existing knowledge, new skills or ideas. This kind of education can happen any where and it can add values to the learner.

Answer:

Explained below.

Explanation:

Conductors can be defined as materials that permit electricity to flow through them easily.

Now, metals have a molecular structure that makes them good conductors because electrons in the atoms of these conductors tend to move freely from one atom to the other. So a majority of metals make good conductors because these metals tend to hold their electrons loosely. In short, it can help engineers make powerful batteries because then it means that they are capable of giving much more electrical energy since nowadays, advanced batteries make use of ion charges for the batteries.

Answer:

PLEASE MARK AS BRAINLIEST!!

Explanation:

ANSWER IS IN THE IMG BELOW

Answer:

a. yes

Explanation:

................

Answer:

the amplitude of the sequence oscillation=

ASO = length × velocity

= 9.8 × 0.2 = 19.6

ASO = 19.6

Answer: Kinetic Energy to Electrical.

Explanation: The magnet is rotated as a result of the spinning wheels, and this results in a powerful stream of electrons, therefore converting kinetic to electrical.

Answer:

Refractive index of the plastic = 1.46

Explanation:

By Snell's law,

[tex]\frac{\text{sin}\theta _{2} }{\text{sin}\theta _{1}}=\frac{n_1}{n_2}[/tex]

Here, [tex]\theta _1[/tex] = Angle of incidence in medium 1 (Plastic)

[tex]\theta_2[/tex] = Angle of refraction in medium 2 (Water)

[tex]n_1[/tex] = Refractive index of medium 1 (Plastic)

[tex]n_2[/tex] = Refractive index of medium 2 (Water)

By substituting values in the formula,

[tex]\frac{\text{sin}(48.7)}{\text{sin}(55.5)}=\frac{1.33}{n_2}[/tex]

[tex]n_2=\frac{1.33\times \text{sin}(55.5)}{\text{sin}(48.7)}[/tex]

    = 1.46

Therefore, refractive index of the plastic = 1.46

Answer:

A thyristor (/θaɪˈrɪstər/) is a solid-state semiconductor device with four layers of alternating P- and N-type materials. It acts exclusively as a bistable switch, conducting when the gate receives a current trigger, and continuing to conduct until the voltage across the device is reversed biased, or until the voltage is removed (by some other means).

Explanation:

Correct me if im wrong

Answer:

velocity = 16.05 m/s

Explanation:

inelastic collision formula:

m1u1 + m2u2 = (m1 + m2)v

m1 = 4kg

u1 = 20m/s

m2 = 15kg

u2 = 15m/s

find v ?

m1u1 + m2u2 = (m1 + m2)v

(4×20) + (15×15) = (4+15)v

80 + 225 = 19v

305 = 19v

19v = 305

v = 305/19

v = 16.05 m/s

Answer:

6.77m/s

Explanation:

Using the law of conservation of momentum

m1u1 + m2u2 = (m1+m2)v

m1 and m2 are the masses of the object

u1 and u2 are the velocities before collision

v is the final collision

Given

m1 = 300g  = 0.3kg

u1 = 6.0m/s

m2 = 10g = 0.01kg

u2 = 30m/s

Required

The bird's speed immediately after swallowing v

Substitute the given values into the formula

m1u1 + m2u2 = (m1+m2)v

0.3(6) + 0.01(30) = (0.3+0.01)v

1.8+0.3 = 0.31v

2.1 = 0.31v

v = 2.1/0.31

v = 6.77m/s

Hence the bird's speed immediately after swallowing is 6.77m/s