what makes 97 of the water on earth unfit for drinking

Answer: that the object is negatively charged.

Explanation:

We know that the force between objects that have the same type of charge is a repulsive force, while for objects with an opposite charge, the force is attractive.

In this case, we know that we have an attractive force between an object and a positively charged rod.

Then the only conclusion we can take in this situation is that the object is negatively charged.

Answer:

[tex]\mathbf{\dfrac{\sigma_{mat}}{L} = 3.6 \ ns/ km}[/tex]

Explanation:

From the given information, the LED is operating with a given wavelength of 850 nm or 0.85 μm.

Hence, the material dispersion is [tex]\dfrac {d \tau _{mat}}{d \lambda } \simeq (80 \ ps / (nm.km) \ )[/tex]

Now, using the pulse spread formula:

[tex]\dfrac{\sigma_{mat}}{L} = \dfrac{d \tau _{mat} }{d \lambda} \sigma \lambda[/tex]

[tex]\dfrac{\sigma_{mat}}{L} = (80 \ ps/ ( m.km) \ ) \times (45 \ nm)[/tex]

Thus, the pulse spreading as a result of  material dispersion is:[tex]\mathbf{\dfrac{\sigma_{mat}}{L} = 3.6 \ ns/ km}[/tex]

The pulses spreading will be 3.6 ns/km. The greatest frequency or the number of pulses per second that may be transmitted into a fiber is pulse spreading.

As an optical pulse travels the length of a fiber, it widens. This feature, which is commonly represented in nanoseconds of widening per kilometer, restricts the usable bandwidth of the Fiber.

The greatest frequency, or the number of pulses per second that may be transmitted into a fiber and anticipated to emerge intact at the other end, has a limit.

This is due to a process known as pulse spreading, which restricts the file's "Bandwidth."

The given data in the problem is;

[tex]\lambda[/tex] is the wavelength = 850 nm

The pulse spreading formula is given as;

[tex]\rm \frac{\sigma_{mat}}{L} =\frac{d \tau_{mat}}{d \lambda} \sigma\lambda \\\\ \rm \frac{\sigma_{mat}}{L} = 80 \times 45 \\\\ \frac{\sigma_{mat}}{L} =3.6 \ ns/km[/tex]

Hence the pulses spreading will be 3.6 ns/km

To learn more about the pulse spreading refer to the link;

https://brainly.com/question/9351212

Answer:

11,627.91 kg/m^3

Explanation:

The computation of the density of the material is shown below

Given that

Mass , m = 1 kg

Height, H - 47 mm = 0.047 m

Diameter, d = 49 mm = 0.049 m

Now radius, r = D ÷ 2

= 0.049 ÷ 2

= 0.0245

Volume = πr^2h

= 3.14 × (0.0245)^2 × 0.047

= 0.000086m^3

Now the density of the material is

= mass ÷ volume

=  1÷  0.000086m^3

= 11,627.91 kg/m^3

Answer: 11,282.8 kg/m^3

Explanation:

We know:

Density = mass/volume

1 kg = mass

(π)(r^2)(h) = volume

Density = m/(πr^2h)

Plug in your values:

Density = 1kg/(π)(24.5 mm)^2(47 mm)

^we have to cut 49 (the diameter) in half because the equation calls for radius

Remember to multiply the density by 10^9 mm/ 1 m because the answer asks for kg/m^3

Answer:

300

Explanation:

If the %DV is based on an average 2,000 calorie diet, and one gram of carbohydrate provides 4 calories, you would divide 2,000 by 4.

2,000 divided by 4 equals 500.

If Anna's doctor recommends 60% of her calories, you find out how much 60% of 500 is.

60% of 500 is 300.

Anna should consume 300 grams of carbohydrates daily.

Hope this helps!

Answer:

300

Explanation:

Explanation:

All of the ways mentioned can be used to determine the mass of the box and pencils contained.

Answer:

D. violet

Explanation:

think of a UV light

Answer:

See explanation

Explanation:

Electric field strength;

E = kq/d^2

k= coulombs constant

q= magnitude of charge

d = distance if separation

If

d is constant

q = 2q

Then;

E = 2 kq/d^2

Hence, the electric field strength will double.

Answer:

194.81 revolutions

Explanation:

Given that,

Initial angular velocity, [tex]\omega_i=3700\ rpm[/tex]

Final angular velocity, [tex]\omega_f=1800\ rpm[/tex]

Time, t = 4.25 seconds

We need to find the number of revolutions occur during this time.

3700 rpm = 387.46 rad/s

1800 rpm = 188.49 rad/s

Let [tex]\alpha[/tex] is angular acceleration. Using first equation to find it.

[tex]\alpha =\dfrac{\omega_f-\omega_i}{t}\\\\\alpha =\dfrac{188.49 -387.463 }{4.25}\\\\\alpha =-46.81\ rad/s^2[/tex]

Now let us suppose that the number of revolutions are [tex]\theta[/tex].

[tex]\theta=\dfrac{\omega_f^2+\omega_i^2}{2\alpha}\\\\=\dfrac{188.49 ^2-387.463 ^2}{2\times -46.81}\\\\=1224.087\ rad[/tex]

or

[tex]\theta=\dfrac{1224.087}{2\pi}\\\\=194.81\ rev[/tex]

Hence, there are 194.81 revolutions.

Answer:

The magnitude of the recoil velocity of the machine is 0.05  m/s.

Explanation:

Given;

mass of the baseball, m₁ = 0.101 kg

mass of the machine, m₂ = 67.1 kg

velocity of the baseball, v₁ = 32.6 m/s

let v₂ be the recoil velocity of the machine.

Apply the principle of conservation of linear momentum; the total momentum before and after firing the ball must be constant.

sum of the initial momentum of the ball and the machine = 0  (at rest)

sum of the final momentum of the ball and the machine = m₁v₁ + m₂v₂

Since total momentum is constant; m₁v₁ + m₂v₂ = 0

m₁v₁ + m₂v₂ = 0

(0.101 x 32.6) + (67.1)v₂ = 0

67.1v₂ = -3.2926

v₂ = (-3.2926) / 67.1

v₂ = -0.05  m/s (the negative sign shows that it is the opposite direction)

Thus, the magnitude of the recoil velocity of the machine is 0.05  m/s.

Answer:

The mass remains the same

Explanation:

An ice cube of mass 5g left in the sun in a beaker will have no mass difference.

For this system, mass is conserved.

um I do not know sorry

Explanation:

ummmmmmjjhfgfffff

Answer:

The energy stored in the bungee cord is 43,750 J.

Explanation:

Given;

extension of the bungee cord, x = 25 m

spring constant of the bungee cord, k = 140 N/m

The elastic potential energy stored in the bungee cord is calculated as;

U = ¹/₂kx²

U = ¹/₂(140)(25)²

U = 43,750 J

Therefore, the energy stored in the bungee cord is 43,750 J.

Answer:

d = 114.95 m

Explanation:

Givens:

a = 7.6 m/s^2

t = 5.5 s

v_i = 0 m/s

a = (v_f-v_i)/t

7.6 m/s^2 = (v_f-0 m/s)/5.5 s

v_f = (7.6 m/s^2)*(5.5 s)

v_f = 41.8 m/s

d = [(v_f+v_i)/2]*t

d = [(41.8 m/s)/2]*5.5 s

d = 114.95 m

Answer:

Zero gravity

Explanation:

Astronauts around the earth either in spaceship, a space station or on a space walk appear to be weightless because of the zero gravity in such environment.

Weight is a function of the mass and acceleration due to gravity a body has.

   Weight  = mass  x  acceleration due to gravity

In a place where acceleration due to gravity is 0, the weight would be zero and a person would appear to be weightless.

Answer:

Explanation:

Input​ refers to the amount of energy put into a device, and ​ output​ refers to the amount of energy that comes out. A device may change the type of energy but not the amount. For example, a light bulb's input energy is the form of electrical energy, and its output energy is in the form of light and heat. Efficiency.

Answer:

The height of the ball when the speed of the ball is half of its initial value is 16.5 m

Explanation:

Given;

maximum height reached by the ball, h = 22 m

let the initial velocity of the = u

The equation of maximum height reached by the ball is calculated as;

v = u² - 2gh

where;

v is the final velocity at the maximum height = 0

0 = u² - (2 x 9.8)22

0 = u² - 431.2

u² = 431.2

u = √431.2

u = 20.765 m/s

Half of the initial speed = ¹/₂ x 20.765 m/s = 10.383 m/s

The height of the ball at this half value of speed is calculated as;

v² = u² - 2gh

where;

v is the final speed = 10.383 m/s

u is the initial speed = 20.765 m/s

(10.383)² = (20.765)² - (2 x 9.8)h

(2 x 9.8)h = (20.765)² - (10.383)²

19.6h = 323.379

h = 323.379 / 19.6

h = 16.5 m

Therefore, the height of the ball when the speed of the ball is half of its initial value is 16.5 m

Answer:

The length of the simple pendulum is 0.248 m.

Explanation:

Given;

period of the simple pendulum, T = 1.00 s

let the length of the simple pendulum = L

The period of oscillation of a simple pendulum is calculated as;

[tex]T = 2\pi \sqrt{\frac{l}{g} } \\\\\frac{T}{2\pi } = \sqrt{\frac{l}{g} }\\\\\frac{T^2}{4\pi ^2 } = \frac{l}{g}\\\\l = \frac{gT^2}{4\pi ^2 } \\\\l = \frac{(9.8)(1)^2}{4\pi ^2 } \\\\l = 0.248 \ m[/tex]

Therefore, the length of the simple pendulum is 0.248 m.

Answer:

F = -4/5 W

Explanation:

We will do this exercise in parts, let's start with the data, The ball must be in balance

            B -W = 0

             B = mg                    (1)

where the thrust is given by Archimedes' principle

            B = ρ g V_liquid

In the problem we are told that the volume of the submerged body is 1/5 of the volume of the body, let's use the subscript 2 for the ball and the subscript 1 for the liquid

            V₁ = [tex]\frac{1}{5}[/tex] V₂

if we use the concept of density for the body

            ρ₂ = m / V₂

            m = ρ₂ V₂

We can see that mass and volume are directly proportional, so we can use a rule of three to find the submerged mass. If mass M is in volume V₂ what mass is there in volume V₂ /5

             m₂ = [tex]\frac{V_{2} }{5} \frac{M}{V_{2} }[/tex]

             m₂ = M / 5

we substitute in equation 1

             B = M / 5 g

This is the thrust that is an upward vertical force, therefore to submerge the whole ball we must apply a downward vertical force equal to the rest of the weight, the equilibrium condition in this case is

             B -W - F = 0

             F = B -W

             F = [tex]\frac{M}{5}[/tex] g - M g

             F = -4/5 Mg

             F = -4/5 W

The negative sign indicates that the force is vertical down

Answer:

O²⁻

Explanation:

Number of protons  = 8

Number of neutrons  = 9

Number of electrons  = 10

What type of atom or ion is it = ?

Solution:

Protons are the positively charged particle in an atom

Neutrons do not carry any charges

Electrons are negatively charged particles

 For this atom, the number of protons helps to identify what specie it is; so this is an oxygen atom.

Now,

     Charge  = Number of protons  - Number of electrons

      Charge  =  8  - 10  = -2

The charge on the atom is -2 and so it is an oxygen ion with -2 charge

 The ion is O²⁻

Answer:

if your going 15000 mph all you can do is accelerate  or go fast  unless there is a opposite

Explanation:

Answer:

Inductive reactance is 50.00 ohms

Explanation:

Given the following data;

Voltage = 120v

Frequency = 60Hz

Current = 2.4 A

To find the inductive reactance;

Inductive reactance, XL = V/I

Where;

Substituting into the equation, we have;

XL = 120/2.4

XL = 50.00 ohms

Given that,

A system dissipates 12 J of heat into the surroundings.

28 J of work is done on the system.

To find,

The internal energy of the system.

Solution,

The first law of thermodynamics is used here. According to this law,

[tex]\Delta E=Q-W[/tex]

Q is heat and W is work done

Here,

Q = -12 J is the heat dissipated by the system

W = -28 J is the work done on the system

ATQ,

[tex]\Delta E=(-12)-(-28)\\\\=-12+28\\\\=16\ J[/tex]

So, the change of internal energy of the system is 16 J.

Explanation:

With the change in medium the speed of light wave travel changes. Therefore, the absolute refractive index changes. The speed of light is maximum is vacuum and changes with the change in medium. This is the refractive indices of different medium are different.

The refractive index is the characteristic of the wave that can not change as the wave enters the second medium.

The refractive index of a substance also known as the refraction index or index of refraction is a dimensionless quantity that specifies how quickly light passes through it in optics.

When the refractive index of a substance is increased, the speed of light in the material decreases.

The speed at which light waves travel changes as the medium changes. The absolute refractive index changes.

As a result, the speed of light is greatest in a vacuum and decreases as the medium changes. This is due to the fact that the refractive indices of various media are different.

Hence the refractive index is the characteristic of the wave that can not change as the wave enters the second medium.

To learn more about the refractive index refer to the link;

https://brainly.com/question/14592350

Answer:

0.27 m/s and 0.01 m/s

Explanation:

Given that

Mass of the bullet, m = 3 g = 0.003 kg

Velocity of the bullet, v = 230 m/s

Weight of the rifle, w = 25 N

From this, we know that the mass of the rifle, M = 25/9.8 = 2.55 kg

Using the law of conservation of momentum, we know that

Momentum of the gun = momentum of the bullet

M.g * V.g = m.b * v.b

2.55 * V.g = 0.003 * 230

2.55V.g = 0.69

V.g = 0.69 / 2.55

V.g = 0.27 m/s

If weight of the shooter = 650, then his mass = 650/9.8 = 66.33 kg

The recoil speed of the shooter is

0.69 / 66.33 = 0.010 m/s

Answer:

8.13secs

Explanation:

From the question weal are given

Height H =324m

Required

time it takes to drop t

Using the equation of motion

H = ut + 1/2gt²

Substitute the given values

324 = 0(t)+1/2(9.8)t²

324 = 1/2(9.8)t²

324 = 4.9t²

t² =324/4.9

t² = 66.12

t = √66.12

t = 8.13secs

Hence the time taken to drop is 8.13secs

Answer:

the reading of the balance must decrease

Explanation:

The balance of the span is within a fluid the air, for which it is subjected to the pressure of the same, if we write the equilibrium equation we have

          F_net = B -W - F_armosphere

in this case F_net = 540 N

where the thrust is given by Archimedes' principle which states that the thrust is equal to the weight of the fluid dislodged

          B = ρ g V

in this case the density of the air is

           ρ = 1.1 kg / m³

therefore the value of the thrust is small

the force of the air is

            P = F / A

            F = P A

the air pressure is approximately P = 1 10⁵ Pa

Thus

      B <F_atmosphere

Now we can analyze what happens when we remove the air from the room, the pressure at atmospheric pressure decreases therefore the force of the air decreases, while there is some air the thrust is maintained even when it also decreases since the density of the air decreases when decreasing the Pressure.

Consequently, the reading of the balance changes depending on how the thrust and the air force decreases, in general the air force decreases much faster than the thrust, therefore the reading of the balance must decrease

Hope this helps