if the current is 0.4 A for the 20 ohm resistor, what is the value for the potential difference? ii) Would it be different for the 30 ohm resistor or the same?

Answer:

Attached is the answer

Explanation:

The car’s velocity after the car has traveled 800 m is 74.83 m/sec.

When an item is moving, its velocity is the rate at which its direction is changing as seen from a certain point of view and as measured by a specific unit of time.

Using equation of motion, initial velocity u = 0 and acceleration a = 3.5 unit and distance travelled is 800 m.

v² = u² + 2as

v² = 0 + 2*3.5*800

v² = 5600

v = 74.83 m/sec

The car’s velocity after the car has traveled 800 m is 74.83 m/sec.

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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 am sorry i don't do physics

Answer:

Explanation:

When the mass

m

is being accelerated with an acceleration of

a

,we can say the net force acting in the direction of acceleration is

F

=

m

a

here,it is given that only one force

F

was applied to cause this acceleration, and also given,

m

=

2

K

g

,

a

=

2

m

s

−

2

So,

F

=

2

⋅

2

=

4

N

Answer:

4N

Explanation:

given formula solution

m=2kg F=ma F=2kg×2m/s^2

a=2m/s^2 =4N

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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Answer:

There are six major nutrients: Carbohydrates (CHO), Lipids (fats), Proteins, Vitamins, Minerals, Water.

Explanation:

Answer:

c

Explanation:

speed=distance÷time

40÷10=4

Answer:

Granite is durable, as it is hard and tough.

Gneiss has resistance to pressure and mechanical impacts

Explanation:

Granite is an igneous rock. It is mostly used in building works and construction because they are very durable. They are hard and tough and they have no internal structures.

Gneiss is used for flooring, ornamental stone, tombstones because of the fact that it shows resistances to pressure and also mechanical impacts.

how they are formed in nature:

In nature, granite is formed from the cooling down of hot molten magma and it's solidification before it reaches the surface of the earth.

In nature, gneiss is as a result of igneous rock or sedimentary rocks metamorphosing. Gneiss and granite are kind of similar. When subjected to great heat, granite becomes gneiss

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.

Velocity of sound travels faster in solids than in liquids, and faster in liquids than in gases because "the density of solids is higher than that of liquids, meaning that the particles are closer together."

Answer:

Explanation:

Due to the fact that sound is caused by vibrations, it's more noticeable in liquid because the vibrations may cause ripples in the liquid

Explanation:

Work done is a physical quantity that is defined as the force applied to move a body through a particular distance.

Work is only done when the force applied moves a body through a distance.

    Work done  = Force x distance

The maximum work is done when the force is parallel to the distance direction.

The minimum work is done when the force is at an angle of 90° to the distance direction.

 So to solve this problem;

 multiply the force applied by Zack and distance through which the bull was pulled.

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:

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.

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

Answer:

Gravity is very important to us. We could not live on Earth without it. The sun's gravity keeps Earth in orbit around it, keeping us at a comfortable distance to enjoy the sun's light and warmth. It holds down our atmosphere and the air we need to breathe.

Answer:

Example:

Astronauts reach a distant planet and find it takes eight times as much force to lift objects there than it does on Earth. What is the acceleration due to gravity on this planet?

On this planet the force of gravity is eight times larger. Since the masses of objects are a fundamental property of those objects, they cannot change, that means the value of ​g​ must be eight times larger as well:

[tex]8F_{grav}=m(8g)8F[/tex]

 [tex]=m(8g)[/tex]

The value of ​g​ on Earth is 9.8 m/s2, so 8 × 9.8 m/s2 = 78.4 m/s2.

Answer:

299,792,458 m/s = speed of light

Explanation:

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.

 [tex]\huge\text{Graphs:}[/tex]

The graph of  

• The I-V for Ohmic Metal wire conductor at constant temperature  always shows a straight line between the Current(I) plotted at Y axis and Voltage(V) plotted at X axis. Picture 1

• The I-V graph for Diode shows that first the current is zero but as we increase the potential difference(voltage), it results in the increase in the current. Picture 2

[tex]\Large\textbf{Diode:}[/tex]  

A diode is a device that allows current to flow in only one direction.

[tex]\Large\textbf{Forward and Reverse Biasing:}[/tex]  

Forward Bias, When a diode is forward bias (a voltage in the "forward" direction) then the P-side of the diode is attached to the positive terminal and N-side is fixed to the negative side of the battery which is connected, current flows freely through the device. The forward bias decreases the thickness of potential barrier(The potential barrier barrier in which the charge requires additional force for crossing the region)

Reverse Bias, When a diode is Reverse bias(a voltage in the "backward direction) then the P-side of the diode is connected to the negative terminal and N-side is connected to the positive terminal of the battery which is connected. The reverse bias increases the thickness of the potential barrier resulting in the flow of no current.

 [tex]\Large\textbf{Answer to the Question "Resistance"}[/tex]

The Forward bias decreases the resistance of the diode whereas the reversed bias increases the resistance of the diode. As in forward biasing the current is easily flowing through the circuit whereas reverse bias does not allow the current to flow through it.

Answer:

B

Explanation:

Speed is distance divided by time.

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:

Explanation:

Electric Bulb: In an electric bulb, the filament of bulb gives light because of heating effect of electricity. The filament of bulb is generally made of tungsten metal; having melting point equal to 3380°C.

Electric iron: The element of electric iron is made of alloys having high melting point. Electric heater and geyser work on the same mechanism.

Electric fuse: Electric fuse is used to protect the electric appliances from high voltage; if any. Electric fuse is made of metal or alloy of metals, such as aluminium, copper, iron, lead, etc. In the case of flow of higher voltage than specified, fuse wire melts and protects the electric appliances.

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:

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:

[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]

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

Answer:

a) A force of 367718.75 newtons is needed to get the full airplane safely in the air.

b) The empty airplane would need a runway of 1828.571 meters.

Explanation:

a) This problem can be solved by using the Work-Energy Theorem, which states that work needed by the airplane to get minimum speed is equal to its change in translational kinetic energy, both measured in joules. The resulting formula is presented below:

[tex]F\cdot \Delta s = \frac{1}{2}\cdot m \cdot (v_{f}^{2}-v_{o}^{2})[/tex] (1)

Where:

[tex]F[/tex] - Minimum net force, measured in newtons.

[tex]\Delta s[/tex] - Runway length, measured in meters.

[tex]m[/tex] - Mass of the airplane, measured in kilograms.

[tex]v_{o}[/tex], [tex]v_{f}[/tex] - Initial and final speeds of the airplane, measured in meters per second.

If we know that [tex]m = 350000\,kg[/tex], [tex]v_{o} = 0\,\frac{m}{s}[/tex], [tex]v_{f} = 82\,\frac{m}{s}[/tex] and [tex]\Delta s = 3200\,m[/tex], then the minimum net force needed by the airplane to get itself safely in the air:

[tex]F = \frac{m\cdot (v_{f}^{2}-v_{o}^{2})}{2\cdot \Delta s}[/tex]

[tex]F = \frac{(350000\,kg)\cdot \left[\left(82\,\frac{m}{s} \right)^{2}-\left(0\,\frac{m}{s} \right)^{2}\right]}{2\cdot (3200\,m)}[/tex]

[tex]F = 367718.75\,N[/tex]

A force of 367718.75 newtons is needed to get the full airplane safely in the air.

b) If we know that [tex]m = 200000\,kg[/tex], [tex]v_{o} = 0\,\frac{m}{s}[/tex], [tex]v_{f} = 82\,\frac{m}{s}[/tex] and [tex]F = 367718.75\,N[/tex], then the length of the runway is:

[tex]\Delta s = \frac{m\cdot (v_{f}^{2}-v_{o}^{2})}{2\cdot F}[/tex]

[tex]\Delta s = \frac{(200000\,kg)\cdot \left[\left(82\,\frac{m}{s} \right)^{2}-\left(0\,\frac{m}{s} \right)^{2}\right]}{2\cdot (367718.75\,N)}[/tex]

[tex]\Delta s = 1828.571\,m[/tex]

The empty airplane would need a runway of 1828.571 meters.

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:

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:

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.