A rock falls off a cliff and hits the ground after three seconds. The rock's velocity is 29. 4 m/s when it hits the ground. What is its acceleration of the rock in the downward direction? 0. 31 ms2 3 ms2 9. 8 ms2 88. 2 ms2.

An electrically charged object can be used to attract any object with an opposite charge.

This is due to the fundamental principle that opposites attract and repel in physics.

Electric charge is a fundamental property of matter that gives rise to electromagnetic interactions. An electric charge, whether positive or negative, produces an electric field that surrounds it. This field exerts a force on any other charge in its vicinity that is either attracted to or repelled from it. Electric charge is a fundamental property of matter that produces a variety of electric phenomena. When the charge is concentrated in a localized region of space, the object is electrically charged. When there is a net accumulation of charge in an object, it becomes electrically charged. An electrically charged object produces an electric field in its vicinity, which exerts a force on other charged objects. An electrically charged object can be used to attract objects with an opposite charge or repel objects with the same charge.

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Answer:

true

Explanation:

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Answer:

Kinetic energy = 5400000 J

Height, h = 45.91 m

Explanation:

It is given that,

Mass of the roller coaster train, m = 12,000 kg

Velocity of the train, v = 30 m/s

Kinetic energy is given by :

KE=\dfrac{1}{2}mv^2KE=

2

1

mv

2

KE=\dfrac{1}{2}\times 12000\ kg\times (30\ m/s)^2KE=

2

1

×12000 kg×(30 m/s)

2

KE=5400000\ JKE=5400000 J

So, the kinetic energy of the train at the top speed is 5400000 J.

For height

According to law of conservation of energy :

PEni+KE i=PE f+KE fPE i +KEi

=PEf +KE f

0+5400000\ J=mgh+00+5400000 J=mgh+0

5400000\ J=mgh5400000 J=mgh

h is the height.

5400000\ J=12000\ kg\times 9.8\ m/s^2\times h5400000 J=12000 kg×9.8 m/s

2

×h

h=45.91\ mh=45.91 m

Hence, this is the required solution.

The percentage error when the maximum torque of the machine is determined, neglecting stator impedance is 2.37%.

The induction motor is one of the most widely used electrical machines. In many industrial applications, these machines are used. The main components of this machine are stator, rotor, and end rings. The stator winding is star connected and is rated 200 V, 3-phase, 4-pole, and 50 Hz.

The following are the primary phase parameters:R1 = 0.11,X1 = 0.352,R21 = 0.13,X21 = 0.35,Xm = 14.(1) The impedance of the rotor circuit, (R2/sX2), may be neglected when the rotor slip s is small. As a result, the value of rotor impedance is ignored.

So the equivalent circuit of the motor becomes(2) When the maximum torque of the motor is determined, the stator impedance is ignored. So, the motor's equivalent circuit becomes as follows:(3) In order to calculate the percentage error, we need to calculate the value of maximum torque with and without neglecting the stator impedance. The maximum torque that can be produced by the induction motor is given by the following formula:

Tmax = (3 Vph2/2ωS[X2 + (R2/s)])N/m

Where,Vph = phase voltage

ω = angular velocity

S = slip

N = number of turns per phase

R2 = rotor resistance per phase

X2 = rotor reactance per phase

M = number of poles

Using the given values, we can calculate Tmax with the following formula:

Tmax (neglecting stator impedance)

= (3 × 2002/2 × π × 50 × 0.0303[0.35 + (0.13/0.03)]) N/m

= 439.54 N/m

Tmax (considering stator impedance) = (3 × 2002/2 × π × 50 × 0.0303[0.35 + (0.13/0.03) + 0.352]) N/m

= 429.36 N/m

The percentage error can be calculated as follows:

Percentage error = [(Tmax (neglecting stator impedance) – Tmax (considering stator impedance))/Tmax (considering stator impedance)] × 100

= [(439.54 - 429.36)/429.36] × 100

= 2.37%

Therefore, the percentage error when the maximum torque of the machine is determined, neglecting stator impedance is 2.37%.

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Answer: -4.53×10-6N

Explanation:

The magnitude of the electrostatic force F between two point charges q1 and q2 is directly proportional to the product of the magnitudes of charges and inversely proportional to the square of the distance between them. Like charges repel each other, and opposite charges mutually attract.

Answer:

the answer is 3600 kilometers

When an 80 kg man moving at 120.75 m/s pushes a 53 g stone away from him while lying on a surface with little friction, the stone moves at a speed of 4.6 m/s.

Let the man acquire the speed v in the opposite direction.Let the momentum be conserved here.The momentum of the stone before the push is: p₁ = 0The momentum of the stone after the push is: p₂ = m × vWhere m is the mass of the stoneThe impulse is given as: J = p₂ - p₁Now, we know that the impulse (J) = Force (F) × time (t).

We also know that force is mass × acceleration. Therefore, the impulse can be written as: J = m × a × tUsing these equations we can solve for the acceleration (a).a = J/(m × t)Now, the acceleration is the same for the man and the stone, but the masses are different.

Therefore, the man acquires a speed v that is much smaller than the velocity of the stone. Substituting the given values we get,a = (m₂v₂ - m₁v₁)/(m₂t₂)  =  (0.053 × 4.6)/(80 × t) = 0.00109/t m/s². After equating the forces acting on both the stone and the man, we have;Fman = - Fstone.

This is because the man's speed is in the opposite direction to the stone.Let u be the initial speed of the man before he shoves the stone away from himself.

Using the momentum formula, m1u1 + m2u2 = m1v1 + m2v2.The mass of the stone is 0.053 kg while the man's mass is 80 kg.So,80u + 0.053 × 0 = 80v + 0.053 × 4.6v = (80u) / 0.053+4.6v = (80u) / 0.053v = 120.75u.

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Answer:

Strobe light, computer monitor, tv screen all these are responsible for epilepsy seizures if some one is sensitive towards these lights.

Explanation:

Around 3% of the people are very sensitive towards to the strobe lights. The strobe light explore to the epilepsy and seizure. Certain of the visual seizures trigger to the intensities towards to the seizures. This condition of a person is called photosensitive seizures. This condition is more common among the adolescent and children.

It becomes less frequent as the age going on. It can happen with the light of tv and computer images scrolling. The intense strobe light also responsible for the seizures. If a person facing such type of problem consult to the doctor immediately. Person should avoid extreme environmental light such video games, tv screen computer monitor, strobe light, social media etc.

By finding the specific heat, we can expect that the material of the block is copper or silver (or a mix).

We know that we give 13,500 joules of energy to the metal block (which we assume has a mass of 1kg) and the temperature increases from 15°C to 60°C.

Then the increase is:

60°C - 15°C = 45°C

Then this metal has a specific heat of:

H = 13,500j/(45°C*1 kg) = 300 J/°C*kg

So it could be copper, which has a specific heat of 380J/°C*kg or Silver, which has a specific heat of 240 J/°C*kg (or a mix of these two).

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Newton's first law is a description of the basic property of inertia in our universe. It states that an object at rest will remain at rest, and an object in motion will remain in motion at a constant velocity, unless acted upon by an external force. This law reflects the fundamental principle that objects in the universe tend to maintain their state of motion, whether at rest or in motion, unless acted upon by a force.

Newton's first law, also known as the law of inertia, is a description of the basic property of our universe that objects will maintain their state of motion unless acted upon by an external force. In simpler terms, an object at rest will stay at rest and an object in motion will continue in its motion with a constant velocity unless a force is applied to change its state. This principle is fundamental to understanding the behavior of objects in our universe.

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Answer:

the change in momentum is 2.52 N·s

the constant force on the ball while in contact with the players foot is 126 N

Explanation:

p=momentum

m=mass

v=change in velocity

p=(0.42)(6)

p=2.52

The change in the ball's momentum is 2.52 kgms⁻¹

The constant force exerted by the players foot on the ball is 126 N

From the question,

We are to determine the change in momentum of the ball

Change in momentum calculated by using the formula,

\(\rho = m(v-u)\)

Where \(\rho\) is the change in momentum

\(m\) is the mass

\(v\) is the final velocity

and \(u\) is the initial velocity

From the given information,

\(m = 0.42 \ kg\)

\(u = 12 \ m/s\)

\(v = 18 \ m/s\)

Therefore,

Change in the ball's momentum,

\(\rho = 0.42 (18-12)\)

\(\rho = 0.42 (6)\)

\(\rho = 2.52 \ kgms^{-1}\)

Hence, the change in the ball's momentum is 2.52 kgms⁻¹

For the force exerted by the players foot

Force is given by change in momentum with time

That is,

\(F = \frac{\rho}{t}\)

Where

\(F\) is the force

\(\rho\) is the change in momentum

and \(t\) is the time

From the given information

\(t = 0.020 \ s\)

Therefore,

\(F = \frac{2.52}{0.020}\)

\(F = 126 \ N\)

Hence, the constant force exerted by the players foot on the ball is 126 N

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The monthly energy cost to run the refrigerator is approximately $7.02.

To determine the monthly energy cost to run a refrigerator, we need to know the power consumption of the refrigerator and the number of hours it operates per month.

The power consumption of the refrigerator is usually stated in watts (W). If you know the power consumption in watts, you can convert it to kilowatts (kW) by dividing by 1000.

Let's assume the power consumption of the refrigerator is 100 watts (0.1 kW), and it operates for an average of 24 hours per day. In a month, there are typically 30 days.

To calculate the energy consumption in kilowatt-hours (kWh) per month, multiply the power consumption in kilowatts by the number of hours of operation per month:

Energy consumption = Power consumption (kW) x Operating hours per month

Energy consumption = 0.1 kW x 24 hours/day x 30 days

Energy consumption = 72 kWh

Now, we can calculate the cost of energy for running the refrigerator. Since electricity rates range from 8 cents/kWh (winter) to 11.5 cents/kWh (summer), we'll use an average rate of 9.75 cents/kWh for this calculation.

Monthly cost = Energy consumption (kWh) x Electricity rate (cents/kWh)

Monthly cost = 72 kWh x 9.75 cents/kWh

Monthly cost ≈ $7.02

Therefore, the monthly energy cost to run the refrigerator is approximately $7.02.

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Answer:

Principal focus of concave lens -

★ The point at which rays parallel to principal axis coming from infinity appear to converge after being refracted from concave lens is called the principal focus of concave lens.

________________________

• Additional information -

★ Principal focus - A number of rays parallel to the principal axis after reflection from a concave mirror meet at a point on the principal axis or appear to come from a point after reflection from a convex mirror on the principal axis. This is called principal focus.

To design separate oscillators of 97 kHz and 79 MHz using the NE555 timer and a crystal oscillator.

Follow the steps below:

Designing an oscillator with the NE555 timer for a frequency of 97 kHz:

1. Connect pins 1 (Ground) and 8 (Vcc) of the NE555 to the appropriate power supply.

2. Connect pin 4 (Reset) to Vcc to disable the reset function.

3. Connect pin 5 (Control Voltage) to Ground.

4. Connect a resistor (R1) and a capacitor (C1) in series between pins 6 (Threshold) and 7 (Discharge). Choose values for R1 and C1 to set the desired time constant.

5. Connect pin 2 (Trigger) to the junction of R1 and C1.

6. Connect pin 3 (Output) to an appropriate load or circuit.

7. Provide necessary decoupling capacitors and stabilize the power supply.

8. Adjust the values of R1 and C1 to achieve the desired frequency of 97 kHz.

Designing an oscillator with a crystal oscillator for a frequency of 79 MHz:

1. Choose a crystal oscillator with a resonant frequency of 79 MHz.

2. Connect the crystal oscillator component to the appropriate pins of a suitable oscillator circuit or microcontroller.

3. Provide necessary decoupling capacitors and stabilize the power supply.

4. Configure the oscillator circuit or microcontroller to use the crystal oscillator component as the clock source.

5. Program or adjust the oscillator circuit or microcontroller to generate an output signal with a frequency of 79 MHz.

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Answer:

A healthy diet, low in sugar, caffeine, and alcohol, can promote health and reduce stress.

Explanation:

A healthy diet, low in sugar, caffeine, and alcohol, can promote health and reduce stress. Get adequate sleep: A good night's sleep makes you able to tackle the day's stress more easily. When you are tired, you are less patient and more easily agitated, which can increase stress.

We will have the following:

So, the momentum of the car is 3258.75 kg*m/s.

When a body is moving in the same direction, its relative speed is 6m/s, while when it is moving in the opposite direction, it is 42 m/s.

The units used to measure speed and velocity are the same. The meter is the SI unit for measuring both distance and displacement. The second is the second as defined by the International System of Units. Two meters per second divided by two is the SI unit of velocity and speed.

It is calculable using an intermediary reference frame. The velocity vector sum can be used to represent this simply. vAB = vA - vB is the way to express the relative velocity formula.

velocity is the same as the relative velocities of A and B.

A=24,B=18

Vab=24-18=6m/s

In opposite direction

Vab=24-(-18)=42m/s

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Answer:

150,000N

Explanation:

Force=Mass*Acceleration

F=ma

Mass of the rocket=1000Kg

Acceleration=150 m/s²

Force=1000*150=150,000kgm/s²=150,000N

Answer:

The frequency of the wave is 5 Hz (Hertz), which means it oscillates or cycles 5 times in one second.

Explanation:

The frequency of a wave is the number of times the wave oscillates or cycles in a given period of time. The period of a wave is the time it takes for the wave to complete one cycle.

The period of the wave is given as 0.2 seconds. To calculate the frequency, we can use the formula:

Frequency (f) = 1 / period (T)

So in this case:

f = 1 / 0.2 seconds

The frequency of the wave is 5 Hz (Hertz), which means it oscillates or cycles 5 times in one second.

Formula for frequency:

\(f=\dfrac{1}{T}\)

frequency(measured in Hertz) = 1 / period(measured in seconds)

__________________________________________________________

Given:

\(T=0.2s\)

\(f=?\)

__________________________________________________________

Finding frequency:

\(f=\dfrac{1}{T}\)

\(f=\dfrac{1}{0.2}\)

__________________________________________________________

Answer:

\(\fbox{f = 5 Hertz}\)

To find the current in the solenoid, we can use the formula that relates the magnetic field (B), number of turns (N), current (I), and length (L) of the solenoid:

B = μ₀ * (N/L) * I

Where:

B is the magnetic field (2.20 mT = 2.20 × 10⁻³ T)

μ₀ is the permeability of free space (4π × 10⁻⁷ T·m/A)

N is the number of turns (37.0)

L is the length of the solenoid (6.10 cm = 6.10 × 10⁻² m)

I am the current (to be determined)

Rearranging the formula to solve for I:

I = (B * L) / (μ₀ * N)

Substituting the given values:

I = (2.20 × 10⁻³ T * 6.10 × 10⁻² m) / (4π × 10⁻⁷ T·m/A * 37.0)

Simplifying:

I = 4.70 A

Therefore, the current in the solenoid is approximately 4.70 Amperes.

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If the time period of the pendulum in earth is 1 seconds, then the length  L is 0.24 m. If length in mars is L/2 and acceleration due to gravity is 1/3rd of that of earth, the time period of the pendulum on mars is 1.216 seconds.

The time period of oscillation of a pendulum is the time taken to complete oscillation. It is related to the length l, and acceleration due to gravity g as:

T = 2π √l/g

T for earth = 1 s

g for earth = 9.8 m/s²

then l = T/4π² × g

l = 1/4π²× 9.8 m/s²

 = 0.24 m

If in mars L = L/2 = 0.24 /2 = 0.12 m

g = 9.8 m/s²/3 = 3.22m/s²

Then time period T = 2π × √0.12 m/3.22m/s²

T = 1.216 s.

Therefore, the time period of the Rover's pendulum in mars is 1.216 seconds.

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Answer:

It should be 75 seconds

Explanation:

Because if it takes 25 seconds from 0 to 5 just multiply by 3

when preasure decreases, air expands and it cools

Answer:

D. All of the above

Explanation:

YES

From the given options, Iron, sodium, and calcium are metals. (option d)

A. Iron (Fe): Iron is a metal. It is one of the most abundant elements on Earth and is widely used in construction, manufacturing, and various industries due to its strength and durability. Iron is an excellent conductor of electricity, which makes it essential for electrical applications.

B. Sodium (Na): Sodium is also a metal. It is a highly reactive metal and is commonly found in compounds like sodium chloride (table salt). Sodium is an essential element for living organisms and plays a crucial role in various biological processes.

C. Calcium (Ca): Calcium is a metal. It is an important element for the human body, as it is a major component of bones and teeth. Calcium is also involved in muscle contraction, nerve function, and blood clotting. Moreover, it is used in the production of alloys and as a deoxidizer in metallurgy.

D. All of these: The correct answer is D. All of the options (iron, sodium, and calcium) are metals. They exhibit typical metallic properties such as high electrical and thermal conductivity, metallic luster, and malleability.

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Answer:

the foiley like color doesn't absorb the heat it bounces off of it. it would be much better to have a black blanket

In the polymerase chain reaction (PCR), the extension step typically occurs at a temperature between 68°C and 72°C. This temperature range is commonly used to allow the DNA polymerase enzyme to synthesize complementary strands of DNA by extending the primers that were annealed in the previous step of the PCR cycle.

During the extension step, the DNA polymerase enzyme adds nucleotides to the 3' end of the primers, synthesizing a new DNA strand complementary to the template DNA. The high temperature is necessary to denature the DNA and separate the double-stranded DNA into single strands, providing the template for the DNA polymerase to work on.

It's important to note that while the temperature range mentioned is commonly used, specific PCR protocols may vary depending on the DNA polymerase used and the target DNA being amplified. Researchers may optimize the PCR conditions, including temperature and time, for their specific experimental needs.

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Answer:

30 m/s

Explanation:

Given: initial velocity( vo ) = 72 km/hr (20 m/s) with an acceleration(a) of 2 m/s 2 and with a time of 5 sec.

Find: >>>Finial velocity( vf ) ?

Use this kinematic equation: vf=vo+(a⋅t)

vf=20+(5⋅2)

vf=30m/s

Answer:

d

Explanation:

Pumice is the type of extrusive igneous rock that can float on the water because air bubbles are trapped when molten material erupted from an underground volcano. Hence, option B is the correct option.

Igneous Rock- when molten roacks or the material of the molten rocks are solidified igneous rocks are formed.

Intrusive igneous rocks

This type of rock is made by crystallization below the earth's surface. In this process, the large crystals of this rock are formed when slow colling occurs under such conditions. For example diorite and granite.

Extrusive igneous rocks

Extrusive igneous rocks cool down quickly with the contact of the surface by making small crystals. Amorphous glass is an example of this process when the extrusive igneous rocks cool very quickly.

One other example of extrusive igneous rocks is pumice. Pumice contains holes in it where air bubbles are trapped in the molten metal. Due to this holes pumice become so light that it can float in water.

Thus, Pumice is the type of extrusive igneous rock that can float on the water because air bubbles are trapped when molten material erupted from an underground volcano. Hence, option B is the correct option.

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