11. Which of these is a way to make an electromagnet stronger?
a putting a switch in the electrical circuit
b replacing the iron core with a copper core
© replacing the copper wire with plastic wire
wrapping the wire around the iron core more times

A superheated cloud of gas and dust swirling around a massive object (usually a black hole or neutron star) is called an accretion disk. The correct option is c.

Accretion disk is a heavy object surrounded by flow of gas, plasma, dust, or particles.  The materials surrounding the heavy object orbiting in the gravitational field of the object that loses energy and angular momentum as it slowly spirals inward.

This cloud can reach incredible speeds and temperatures as gravity causes it to build up more and more friction, eventually releasing x rays.

Thus, accretion disk is a superheated cloud of gas and dust swirling around a massive object.

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The current flowing in the 4 ohms resistor connected in series with 5-ohm resistor is determined as 1.0 A.

The equivalent resistance of the circuit is determine as follows;

Rt = R1 + R2

Rt = 4 ohms + 5 ohms = 9 ohms

The current flowing in the 4 ohms resistor is determined from Ohms law as shown below;

V = IR

I = V/R

I = 9/9

I = 1.0 A

Since the circuit is in series arrangement, same current will flow in 5 ohm and 4 -ohm.

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The acceleration of a train that takes 22 seconds to go from a speed of 73 kilometers per hour to a speed of 45 kilometers per hour is 0.354 m/s².

Acceleration: the rate at which the speed and direction of a moving object vary over time. A point or object going straight ahead is accelerated when it accelerates or decelerates.

Even if the speed is constant, motion on a circle accelerates because the direction is always shifting.

Acceleration is a change in velocity divided by a change in time. Given the time of 22 seconds and the distance is 73 kilometers. The speed is 45 k/h

(73 - 45 ) = 28 km / hr  

Change in velocity = 7.778 m/s

7.778 m/s / 22 s  = 0.354 m/s².

Therefore, the acceleration of a train is 0.354 m/s².

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Answer:

Below

Explanation:

73 km / hr = 20.277 m/s     and     45 km/hr = 12.50 m/s

Acceleration = change in velocity / change in time

                      (12.5 - 20.277) m/s  / 22 s =  - . 354 m/s^2  

                           ( NOTE the negative sign....this is a DEceleration)

Answer:

molecules

Explanation:

Molecules will be formed if atoms join together.

Answer:

the rainbow spectrum. red orange yellow green blue violet. It breaks into ultra violet.

Explanation:

Answer:

Approximately [tex]15\; {\rm m\cdot s^{-1}}[/tex] (assuming that [tex]g = 9.81\; {\rm m\cdot s^{-2}}[/tex].)

Explanation:

Let [tex]m[/tex] denote the mass of this vehicle, and let [tex]g[/tex] denote the gravitational field strength.

Since the road is level, the normal force that the road exerts on the vehicle would be equal in magnitude to the weight [tex]m\, g[/tex] of this vehicle. That is: [tex]F_\text{normal} = m\, g[/tex].

Let [tex]\mu_{k}[/tex] denote the coefficient of (kinetic) friction between the tires of this vehicle and the road. The maximum friction that the road could exert on this vehicle would be:

[tex]\begin{aligned}& F_\text{max. friction} && (\text{max. friction}) \\ =\; &\mu_{k}\, F_\text{normal} && (\text{coefficient of friction}) \,(\text{normal force}) \\ =\; & \mu_{k}\, m\, g\, \end{aligned}[/tex].

Also because this road is level, the only unbalanced force on this vehicle would be friction. Thus, the net force on this vehicle would be equal to the friction that the road exerts on the vehicle, which is at most [tex]\mu_{k}\, m\, g[/tex]:

[tex]\begin{aligned}& F_\text{net} && (\text{net force}) \\ =\; & F_\text{friction} && (\text{friction}) \\ \le \; & F_\text{max. friction} && (\text{max. friction})&\\ =\; & \mu_{k}\, m\, g\, \end{aligned}[/tex].

In other words, [tex]F_\text{net} < \mu_{k}\, m\, g[/tex]. This inequality could provide an upper bound on the acceleration of this vehicle:

[tex]\begin{aligned}& a && (\text{acceleration}) \\ =\; & \frac{F_\text{net}}{m} && \genfrac{}{}{0em}{}{(\text{net force})}{(\text{mass})}\\ \le \; & \frac{\mu_{k}\, m\, g}{m} \\ =\; & \mu_{k}\, g\end{aligned}[/tex].

Thus, the maximum acceleration of this vehicle on this road would be [tex]a_\text{max} = \mu_{k}\, g[/tex].

Let [tex]r[/tex] denote the radius of this circle. When the vehicle is moving around this circle at a speed of [tex]v[/tex], the (centripetal) acceleration of this vehicle would continuously be [tex]a = (v^{2} / r)[/tex].

Since the upper bound of the acceleration of this vehicle is [tex]a_\text{max} = \mu_{k}\, g[/tex], rearrange the equation [tex]a = (v^{2} / r)[/tex] to find an upper bound on speed [tex]v[/tex]:

[tex]\begin{aligned}\frac{v^{2}}{r} &= a \\ & \le a_{\text{max}} \\ &= \mu_{k}\, g\end{aligned}[/tex].

[tex]v^{2} \le \mu_{k}\, g\, r[/tex].

[tex]v \le \sqrt{\mu_{k}\, g\, r}[/tex].

In other words, when the radius of the circle is [tex]r[/tex], the coefficient of friction between the tire and the ground is [tex]\mu_{k}[/tex], and the gravitational field strength is [tex]g[/tex], the maximum speed of the vehicle would be [tex]\sqrt{\mu_{k}\, g \, r}[/tex].

In this question, it is given that [tex]r = 40.0\; {\rm m}[/tex] whereas [tex]\mu_{k} = 0.60[/tex]. Assuming that [tex]g = 9.81\; {\rm m\cdot s^{-2}}[/tex], the maximum speed of this vehicle would be:

[tex]\begin{aligned}v_\text{max} &= \sqrt{\mu_{k}\, g\, r} \\ &= \sqrt{0.60 \times 9.81\; {\rm m\cdot s^{-2}} \times 40.0\; {\rm m}} \\ &\approx 15\; {\rm m\cdot s^{-1}}\end{aligned}[/tex].

The statement 'research indicates that high serotonin levels may increase aggression' is FALSE.

Serotonin is a chemical messenger (i.e., a hormone) used to transmit messages through the body.

In conclusion, the statement 'research indicates that high serotonin levels may increase aggression' is FALSE.

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Answer:

it takes 3 hours to travel

Explanation:

120 ÷ 40 = 3

Step 1. distance = speed * time or time = distance/speed. 

Step 2. time = 120 miles/(40 miles/hour) = 3 hours. 

Step 3. ANSWER: It would take 3 hours to travel 120 miles at 40 mph. 

Power is the energy per unit time required to run a machine. The output power of the motor is 2590 W.

Power is the product of force and velocity with which an object is moving.

P = F x v

Given is the force 450N and the velocity is 5.675 m/s, then the power is

P = 450 x 5.75

P = 2587.5 Watt

The power output of the motor is approximately 2590 W.

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F = G M.m/r²

F = force, N

G = gravitational constant,  6.67 x 10⁻¹¹ Nm²/kg²

m,M = mass of object,  kg

r = distance, m

F = 6.67 x 10⁻¹¹ x 69.3 x 52/1.2²

F = 1.669 x 10⁻⁷

Hence,the time it takes the second cyclist to catch up to the first cyclist will be 2.6 h.

The change of displacement with respect to time is defined as the velocity.  Velocity is a vector quantity. it is a time-based component.

[tex]\rm D_{rel}= V_{rel}\times t_{rel} \\\\ \rm D_{rel}= (V_1-V_2)\times t_{rel} \\\\ T_{rel}=\frac{D_{rel}}{V_1-V_2} \\\\ T_{rel}=\frac{20.8}{28-20} \\\\ T_{rel}= 2.6 \ h[/tex]

The time it takes the second cyclist to catch up to the first cyclist will be 2.6 h.

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Answer:

True

Explanation:

because their is friction(e.g take a ruler rub it in your hair then put it on top of a piece of paper on the table then u will see the process)among the two objects.

Answer:

No

Explanation:

It will never decay to zero

after one half life there is 1/2 left

  after the next half life thee is   1/2 * 1/2 = 1/4 left

     then 1/8th    then  1/16 th   then   1/32     1/64     1/128 ........to infinity  

        while htere is a VERY small amount left , there will never be ZERO left

You should keep your eyes on the road and shift into neutral when gas pedal gets jammed.

In automobiles, shifting into neutral won't transmit power to the wheels and the direction of the steering wheel can still be controlled.

This helps to prevent accidents on the road as a result of such malfunctions in the car.

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The vibrational period of the rope, when a student shakes it is 0.25 s.

Frequency is the number of oscillations per second.

Given is the number of vibrations =36 in time t = 9s, then frequency will be

f = 36/9 =4Hz

The time period is the reciprocal of the frequency.

T = 1/f

Plug the frequency value, we get

T = 1/4 Hz = 0.25 seconds

Thus, the vibrational time period is 0.25s.

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If you touch a conductor through which electricity flows with an insulator, the likelihood of receiving a shock depends on several factors, including the voltage and current of the electrical source, the amount of insulation present, and how well the insulation is able to insulate from the electricity.

Insulators are materials that do not conduct electricity and are commonly used to provide a barrier between humans and electrical conductors to prevent electrical accidents. When an insulator is used to touch a conductor through which electricity flows, the insulator acts as a barrier and prevents the current from flowing through the material and into the body.

However, if the insulation is inadequate or damaged, or the voltage of the electrical source is high enough to overcome the insulating properties of the material, a shock can occur. The shock occurs when the current passes through the body, causing damage to organs, muscles, and nerves.

Therefore, it is important to ensure that proper insulation practices are followed when working with electrical conductors, and to use insulation materials that are sufficient to protect against the voltage and current levels of the electrical source being used. Generally, it is recommended to avoid touching electrical conductors altogether, as the risk of electrical accidents is always present.

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No, you will not receive a shock if you touch a conductor through which electricity flows with an insulator. An insulator is a material that does not conduct electricity, meaning it does not allow the flow of electric current.

It has high resistance and acts as a barrier, preventing the transfer of electrons. Therefore, when you touch a conductor with an insulator, the insulator acts as a protective layer that blocks the flow of electric current and prevents it from reaching your body. As a result, you will not experience a shock. However, it is important to note that the effectiveness of the insulator in preventing a shock depends on its quality and condition. If the insulator is damaged or has a low resistance, it may not provide adequate protection, and there is a risk of electric shock. Additionally, it is crucial to follow safety protocols and avoid touching conductors or working with electricity unless you are trained and have the necessary knowledge and equipment to do so safely.

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Answer:

Soln,

force=3000 N

distance=75 m

we know that,

work done= force × distance

= 3000× 75

= 225000 joule

Explanation:

It is due to cohesion (option C)

Answer:

90 watts

Explanation:

Formula for Power (using voltage and current) :

Answer:

90 watts

Explanation:

Watts = volts x amperes

120X.75 = 90

Saturated fats have the maximum number of hydrogens possible, while unsaturated fats consists of a double bond between two of the carbon atom.

The partially hydrogenated fats useful for making potato chips but not particularly healthy for humans to eat because of presence of trans fat.

Partially hydrogenated fats have trans fat that can raises cholesterol level in heart and result in severe health complications like heart attack.

Each carbon have four bonds to react with.  In saturated fats, each carbon has four hydrogens bonded and a straight structure is formed  They are solid at room temperature. So, they are remain solid in arteries of heart and block it.

Unsaturated fats have a carbon, double bonded with another carbon and gives the molecule a bent structure. They remain liquid at room temperature and are healthier fats.

The potato chips are not healthy for humans to eat. The partially hydrogenated fats raise bad cholesterol and lowers good cholesterol. The trans fats increases the risk of heart disease and can lead to death of adults. The more trans fats eaten, the greater is the risk of heart attack.

Thus, partially hydrogenated fats useful for making potato chips but not particularly healthy for humans to eat because of presence of trans fat.

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Answer:

Pluto

Explanation:

Pluto is now classified as a dwarf planet It used to be a formal planet but not anymore.

Answer:

Net force is found by sum of the forces.

Answer:

The correct answer is When two forces act in the same direction on an object, the net force is found by the sum of the forces.

Hope this helps you!!

Please mark me Brainleast!!

Answer:

option B...

they represent different concept...

i hope this will answer your question

The sound produced by an instrument of length L that is open at one end posses has a high frequency.

Sound is kind of vibration which travels in the form of sinusoidal wave through a medium which can be solid, liquid or gas/air.

Sound produced by an instrument which has an open end has a high

frequency and pitch, nodes , timbre and a low antinode. These are all the characteristics of a sound produced by the instrument.

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A diverging lens is used to permit clear vision of an object placed at infinity. The focal length of the lens is -100 cm.

The focal length is half of the radius of curvature of the focal lens.

By the lens maker formula,

1/f = 1/v +1/u

where, v is the image distance and u is the object distance.

Give, the object is at infinity and the image must form at 100 cm, the the focal length will be

1/f = 1/ -100 + 1/∞

f = -100 cm

The focal length must be -100 cm for the diverging lens.

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Answer:

0. 75A

Explanation:

R1=20omh

R2=20omh

R3=20omh

equivalent voltage (V)= 5.00V

equivalent resistance (R) = ?

equivalent current (I)= ?

since, they are in parallel so,

1/R = 1/R1 + 1/R2 + 1/R3

1/R = 1/20 + 1/20 + 1/20

1/R = 3/20

R = 6.67 ohm

Now,

from ohm's law

V= IR

or, 5 = 6.67*I

or, I = 0.749

hence, I= 0.75A

Answer:

In the core of the Sun hydrogen is being converted into helium. This is called nuclear fusion. It takes four hydrogen atoms to fuse into each helium atom. During the process some of the mass is converted into energy.

Answer:

It's D, they're all radioactive. This is due to the molecules that it is made up of

Answer:

the answer is A

Explanation:

I hope it helps you

Answer:

b i think

Explanation: