please help will give brainlyest

Answer: I think Windows.

Explanation: The absorption of light makes an object dark or opaque to the wavelengths or colors of the incoming wave: Wood is opaque to visible light. Some materials are opaque to some wavelengths of light, but transparent to others. Glass and water are opaque to ultraviolet light, but transparent to visible light.

Option.D-All materials is the correct answer.
Any object, whether living or inert, has the ability to absorb light. Absorption is always influenced by the electromagnetic frequency of the light being transmitted (i.e., its color) and the composition of the object's atoms.

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Answer: I believe the correct answer is A.

Answer:

25 km/h

Explanation:

speed=distance÷time

125÷5=speed

125÷5=25 (then add units)

Answer:

I guess that the atoms are:

Protons:     6     8    5    2    12    12

Neutrons:  8     8     5   3     13    14

Now, two atoms are isotopes if they share the same number of protons (so both atoms are the same element) but they have a different number of neutrons.

From the given options, the only two that have the same number of protons but a different number of neutrons are:

Protons 12, neutrons 13

and

Protons 12, neutrons 14.

These two are isiotopes.

Answer:

20 Hz, 20000 Hz

0.0166 m, 16.6 m

Explanation:

The minimum frequency that a human ear can hear is 20 Hz

The maximum frequency that a human ear can hear is 20000 Hz.

v = Velocity of sound = 332 m/s

Wavelength is given by

[tex]\lambda=\dfrac{v}{f}\\\Rightarrow \lambda=\dfrac{332}{20}\\\Rightarrow \lambda=16.6\ \text{m}[/tex]

The longest wavelength that can be heard by the human ear is 16.6 m

[tex]\lambda=\dfrac{332}{20000}\\\Rightarrow \lambda=0.0166\ \text{m}[/tex]

The shortest wavelength that can be heard by the human ear is 0.0166 m.

Answer:

Because in order for work to be done on an object, the object must be moving. Why isn't work being done on a barbell when a weight lifter is holding the barbell over his head? Work is maximized when force is applied in the same direction that the object is moving. ... In order to do work faster, more_is required.

Answer:

I think it is A or B, but more B as for John used 20 more net force. I recommend doing some research, sorry.

Answer:

I think the answer is B, I may be wrong...

Explanation:

Answer: Optical test is a test which is used to assess vision and ability of the person to focus on the objects.

Explanation:

The following are the advantages of utilizing plane mirror in optical testing:

1. When a plane mirror is used for testing the image of the test card must be placed at distance equal to the distance of the object.  

2. Larger distance in between the object or test card and viewer is obtained. This can help in determining the exact ability of the eye to focus on objects.

Answer:

Gravity creates stars and planets by pulling together the material from which they are made.

Explanation: Thats the only thing i have im stuck on the tga quiz

The point B represent the crest of the wave. The crest is the peak of the wave. While the trough is the lowest.

The distance between two successive troughs or crests is known as the wavelength.

The wavelength is also defined as the distance between two locations in a wave that have the same oscillation phase.

The point B represent the crest of the wave. The crest is the peak of the wave. While the trough is the lowest.

Hence, option B is correct.

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Answer:

Approximately [tex]5.5\; \rm N[/tex], assuming that the volume of these two charged objects is negligible.

Explanation:

Assume that the dimensions of these two charged objects is much smaller than the distance between them. Hence, Coulomb's Law would give a good estimate of the electrostatic force between these two objects regardless of their exact shapes.

Let [tex]q_1[/tex] and [tex]q_2[/tex] denote the magnitude of two point charges (where the volume of both charged object is negligible.) In this question, [tex]q_1 = 20 \times 10^{-6}\; \rm C[/tex]  and [tex]q_2 = 15 \times 10^{-6}\; \rm C[/tex].

Let [tex]r[/tex] denote the distance between these two point charges. In this question, [tex]r = 0.7\; \rm m[/tex].

Let [tex]k[/tex] denote the Coulomb constant. In standard units, [tex]k \approx 8.98755\times 10^{9}\; \rm kg \cdot m^{3}\cdot s^{-2}\cdot C^{-2}[/tex].

By Coulomb's Law, the magnitude of electrostatic force (electric force) between these two point charges would be:

[tex]\begin{aligned}F &= \frac{k \cdot q_1 \cdot q_2}{r^{2}}\end{aligned}[/tex].

Substitute in the values and evaluate:

[tex]\begin{aligned}F &= \frac{k \cdot q_1 \cdot q_2}{r^{2}}\\ &\approx 8.98755 \times 10^{9}\; \rm kg \cdot m^{3}\cdot s^{-2}\cdot C^{-2} \\ &\quad \times 20\times 10^{-6}\; \rm C\\ &\quad \times 15\times 10^{-6}\; \rm C \\ &\quad \times \frac{1}{{(0.7\; \rm m)}^{2}}\\ &\approx 5.5\; \rm N \end{aligned}[/tex].

Answer:

D is the correct answer

Explanation:

Ek=m*g*h=50*9.8*5=2450

The kinetic energy right before she hits the water is 2450J. So, the correct option is D.

Kinetic energy is defined as the energy that is due to the motion of an object. If we want to accelerate an object, we must apply a force, by applying a force we need to do work. After the work is done, energy has been transferred to the object, and the object will continue to move with a new constant speed.

A 50Kg girl jumps off a 5-meter-high diving board.

We need to find the kinetic energy of the girl before she enters the water which means that the kinetic energy becomes equal to the potential energy such that,

P.E.=K.E. = mgh

where, m=mass of the object

g= acceleration due to gravity [tex](9.8m/s^2)[/tex]

h= height

So, K.E= 50* 9.8*5 = 2450 J

Thus, the kinetic energy right before she hits the water is 2450J. So, the correct option is D.

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0.184[tex]m^{3}[/tex] is the answer for Acellus students!

Answer:

Free body diagram

Explanation:

A free body diagram shows all the forces acting on a body. Since force is a vector quantity, the magnitude and direction of the forces are shown in the free-body diagram.

Force is the push or pull on a body.

It can be via contact or without contact. Such non-contact forces acts via a force field.

In physics, this free body diagram is used extensively.

element z are isotopes because number of netron are different and number of protons are same

Resistance is a material's tendency to resist the flow of charge (current). Resistance is the measure of the opposition to motion of free electrons(current) due to their continuous collisions with the atom of the lattice. An electric current flows when electrons move through a conductor, such as a metal wire. The moving electrons can collide with the atoms in the metal. This makes it more difficult for the current to flow, and causes resistance. The unit of Resistance is "OHM". Ohm is denoted by the greek letter "Ω".

  If a current 'I' is caused to flow in a conductor by a battery of potential difference 'V', it is found that the current is directly proportional to potential difference provided there is no change in the conductor itself. That means more will be I if we increase V. So

                     [tex]{\Longrightarrow}\qquad \qquad \qquad I {\propto} V\\\\{\Longrightarrow}\qquad \qquad \qquad I = KV[/tex]

Where K is Conductance. Conductance is the ability of a conductor to allow the current to pass through it.  Resistance(R) is the reciprocal(opposite) of conductance(K) thus K is inversely proportional to R,

                     [tex]{\Longrightarrow}\qquad \qquad \qquad I = \frac{1}{R}V \\\\{\Longrightarrow}\qquad \qquad \qquad V = IR[/tex]

This is known as OHM's Law, and V = IR is the equation linking the R, V and I.

[tex]\Huge\text{Circuit Diagram:}[/tex]

Circuit Diagram no 1 attached is of this question. In the circuit diagram, V is voltmeter to find the potential difference, A is the ammeter to find the current, R is the resistance i.e. the conductor wire, The switch and the battery.

Suppose the wire of length 100 cm is connected to a battery, the Voltmeter observes the potential difference and ammeter reads the current of the wire. We will use the R, V and I i.e. V = IR equation to find out the resistance of that wire and Record the resistance. Then attach another small wire of suppose 90 cm to the battery, and similarly Find out its resistance too. After recording the resistance 3 or 4 times, you will observe that When you decrease the length of the wire,

The resistance of a conductor depends upon the following factors.

                   [tex]{\Longrightarrow}\qquad \qquad \qquad R\quad {\propto}\quad L[/tex]    

                   [tex]{\Longrightarrow}\qquad \qquad \qquad R\quad {\propto}\quad \frac{1}{A}[/tex]

The relation between only length of the wire and resistance is [tex]R\quad {\propto} \quad L[/tex] . The relation of R, L and A is given by, ρ

                    [tex]{\Longrightarrow}\qquad \qquad \qquad R\quad {\propto}\quad \frac{L}{A}\\\\{\Longrightarrow}\qquad \qquad \qquad R\quad =\ \frac{\ {\rho}\ L\ }{A}[/tex]

Where ρ is known as resistivity depends upon the nature of the material of the wire. The meter of resistivity is Ω x m(Ohm x meter).

[tex]\Huge\text{I-V Characteristic:}[/tex]

I-V curves of an electrical device or component, are a set of graphical curves which are used to define its operation within an electrical circuit. I-V characteristic curves show the relationship between the current flowing through an electronic device and the applied voltage across its terminals. The circuit diagram to find I-V characteristic must have a resistor which is a device or component connected to a battery which is providing the potential difference V. When a resistor is connected to a battery, current I is observed due to drift velocity. To find the current and potential difference(voltage) the circuit must have the Ammeter and voltmeter. Recorded current and voltage must be used to plot the graph to check the I-V characteristic. The picture attached is the circuit diagram.

We calculate the resistance at constant temperature by ohm's law. The Ohms law is applied at constant temperature because the resistance of any material varies with the change in temperature. It shows a linear relationship between the applied voltage and the resulting current, resistance being a constant. So we could use V = IR because resistance is constant at constant temperature.

Answer:

Total momentum = 50kgm/s

Explanation:

Given the following data;

Mass, M1 = 5kg

Mass, M2 = 7kg

Velocity, V1 = 10m/s

Velocity, V2 = 0m/s (since it's at rest).

To find the total momentum;

Momentum can be defined as the multiplication (product) of the mass possessed by an object and its velocity. Momentum is considered to be a vector quantity because it has both magnitude and direction.

Mathematically, momentum is given by the formula;

[tex] Momentum = Mass * Velocity [/tex]

The law of conservation of momentum states that the total linear momentum of any closed system would always remain constant with respect to time.

Total momentum = M1V1 + M2V2

Substituting into the equation, we have;

Total momentum = 5*10 + 7*0

Total momentum = 50 + 0

Total momentum = 50 kgm/s

Therefore, the total momentum of the bowling ball and the putty after they collide is 50 kgm/s.

Answer:

90m/s

Explanation:

Given parameters:

Acceleration  = 10m/s²

Time of fall  = 9s

Unknown:

Final velocity  = ?

Solution:

We can assume that the cart falls from rest.

   Initial velocity  = 0m/s

Using

        v  = u + gt

v is the final velocity

u is the initial velocity

g is the acceleration due to gravity

t is the time

       v  = 0 + 10 x 9  = 90m/s

Answer:

90m/s

Explanation:

Answer:

The new force is 2/3 of the original force

Explanation:

Coulomb's Law

The electrical force between two charged objects is directly proportional to the product of their charges and inversely proportional to the square of the distance between the two objects.

Written as a formula:

[tex]\displaystyle F=k\frac{q_1q_2}{d^2}[/tex]

Where:

[tex]k=9\cdot 10^9\ N.m^2/c^2[/tex]

q1, q2 = the objects' charge

d= The distance between the objects

Suppose the first charge is doubled (2q1) and the second charge is one-third of the original charge (q2/3). Now the force is:

[tex]\displaystyle F'=k\frac{2q_1*q_2/3}{d^2}[/tex]

Factoring out 2/3:

[tex]\displaystyle F'=\frac{2}{3}k\frac{q_1*q_2}{d^2}[/tex]

Substituting the original force:

[tex]F'=\frac{2}{3}F[/tex]

The new force is 2/3 of the original force

None can.

A clinical thermometer only measures temperatures above +30°C.

Mercury and alcohol are both frozen solid at -50°C.

For this use the formula:

d = Vo * t - (at^2) / 2

Clearing t:

t = d/(v + 0.5*a)

Replacing:

t = 5 m / (7.2 m/s + 0.5 * (-1.1 m/s²)

Resolving:

t = 5 m / (7.2 m/s + (-0.55 m/s²)

t = 5 m / 6.65 m/s

t = 0.75 s

Result:

The time will be 0.75 seconds.

If an object is given an initial velocity in any direction and then allowed to travel freely under gravity, it is called a projectile motion.

It is basically 3 types.

Answer:

C M (change in T) = heat absorbed      thermal equation for heat gained

C = 418.4 J / (2 kg * 50 deg K) = 4.184 J / kg * deg K     specific heat

Note: 1 gm =.001 kg

So C = .004184J / gm * deg K

Also, 1 J = .239 cal   so in conventional terms

C = .001 cal / gm deg K     (very low, water would be 1 cal / gm deg C

Answer:

[tex]1.5\cdot 10^{-5}\:\mathrm{N}[/tex]

Explanation:

Newton's Law of Gravitation is given as:

[tex]F=G\frac{m_1m_2}{r^2}[/tex], where [tex]G[/tex] is gravitational constant [tex]6.67\cdot 10^{-11}[/tex] and [tex]r[/tex] is the distance between their centers of mass.

Therefore, the gravitational force between them is:

[tex]F=6.67\cdot 10^{-11}\frac{55\cdot40}{0.1^2}= \fbox{$1.5\cdot 10^{-5}\:\mathrm{N}$}[/tex] (two significant figures).

Answer:

2.5m/s²

Explanation:

Given parameters:

Mass of car  = 1400kg

Resultant force  = 3500N

Speed  = 30m/s

Unknown:

Average acceleration = ?

Solution:

According to the Newton's second law of motion:

     Force  = mass x acceleration

Now;

       3500 = 1400 x acceleration

      Acceleration  = [tex]\frac{3500}{1400}[/tex]   = 2.5m/s²

Answer:

B

Explanation:

Speed is distance divided by time.

Answer:

[tex]F=683.790939[/tex]N

Explanation:

From the Question we are told that

Earth mass [tex]m_1= 5.98 * 10^2^4 kg[/tex]

Students mass [tex]m_2=70kg[/tex]

Distance of student from earth center Radius [tex]r=6.39 * 10^6 m[/tex]

Generally the equation for Force of attraction b/w the earth and the boy is mathematically given by

 [tex]F=\frac{Gm_1m_2}{r^2}[/tex]

 [tex]F=\frac{6.67.10^-^1^1*( 5.98 x 10^2^4)(70)}{(6.39 *10^6)^2}[/tex]

Therefore the force of attraction b/w the student and the earth is

 [tex]F=683.790939N[/tex]

 [tex]F\approx 684N[/tex]

Answer:

c

Explanation:

speed=distance÷time

40÷10=4

Answer:

Objects; waves.

Explanation:

Waves interact with objects and other waves. Thus, waves are used on objects such as mobile phones and can be transformed from one form to another.

There are various types of waves in our physical environment such as gamma rays, x-rays, ultraviolet waves, radio waves etc.

Radio waves can be defined as an electromagnetic wave that has its frequency ranging from 30 GHz to 300 GHz and its wavelength between 1mm and 3000m. Therefore, radio waves are a series of repetitive valleys and peaks that are typically characterized of having the longest wavelength in the electromagnetic spectrum.

Basically, as a result of radio waves having long wavelengths, they are mainly used in long-distance communications such as the carriage and transmission of data. Some examples of communication technologies that uses radio waves are radio set, mobile phones, television etc.