What are challenges faced by both modern and ancient engineers?

Answers

Answer 1

Answer:

Climate Chrises

Explanation:


Related Questions

a force of 50 N directed 30 degrees above the horizontal is applied to a 10 kg block at rest on a rough horizontal surface. what is the coefficient of kinetic friction between the block and the horizontalsurface if the acceleration of the block is 20 m/s^2

Answers

The coefficient of kinetic friction between the block and the horizontal surface will be 1.597.

What is kinetic friction?

A force that acts among sliding parts is referred to as kinetic friction. A body moving on the surface is subjected to a force that opposes its progressive motion.

The given data in the problem is;

μ is the coefficient of kinetic friction=?

m is the mass of the block=10 kg

g is the acceleration due to gravity= 9.81 m/s²

Acceleration of block(a)=20 m/s²

Force (F)= 50 N

θ=30°

There are two forces to act on the block, one is the force directed while the other was the friction force opposing the motion.

From the newton's second law;

F= ma

F-f = ma

Fcos30°- μmg=ma

50cos 30°-μ× 10×9.81 =10 × 20

μ= 1.597

Hence, the  coefficient of kinetic friction will be 1.597.

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I need some help with this question

Answers

the answer for number 2 is B

When two objects made of different materials are rubbed together, they will attract each other after the charging process.Immersive Reader (1 Point) True False

Answers

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.

The half-life of gold-198 is 2.7 days. After 5.4 days, how much of the original gold-198 remains?
A. one-half B. one-quarter C. all D. none​

Answers

The the amount of the original gold-198 that remains after 5.4 days is one-quarter.

What is half-life?

Half-life is the time required or taken for half the amount of matter present in a given substance to vanish or decay.

The half-life of gold-198 is 2.7 days.

After, 5.4 days, the gold would have undergone two half-lives.

The amount of matter remaining = 1/2 * 1/2 = 1/4

Therefore, the amount of the original gold-198 that remains is one-quarter.

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Can someone please answer this, ill give you brainliest Would be very appreciated.

Answers

Answer: Through Photosynthesis

Explanation:

Answer:

Option 3

Explanation:

Carbon is cycled into the hydrosphere through the diffusion from the atmosphere.

Further explaining this :

Some of the carbon dioxide molecules in the rain react with the water droplets to form carbonic acid that falls with the rain. The carbonic acid that falls to the surface of the Earth dissolves rocks by the process of chemical weathering, where it releases calcium, magnesium, potassium or sodium ions. These ions are carried by rivers to the ocean. The carbonic acid that falls directly into surface water bodies reacts with the water to form bicarbonate ions.

What kind of atmosphere surrounds mercury?
none
carbon dioxide
methane
dense clouds

Answers

Answer:

None

Explanation:

Mercury does not have a atmosphere because it is simply to hot. Because of its temperature it's atmosphere is constantly being replenished as the atoms escape into space.

how do you get this equation?
please help

Answers

Answer:

It's a kinematic equation.

Explanation:

x displacement = (velocity_final * time) - (0.5 * acceleration * time * time)

You should be given a value, context(word problem), or diagram.

If you're deriving for a term just isolate the term.

If you're asking why the -(0.5 * acceleration * time * time) is negative instead of positive, would need context.

A nearsighted eye has a far point of 100 cm. Objects further than 100 cm are not seen clearly. A diverging lens is used to permit clear vision of an object placed at infinity. Find the focal length of the lens.

Answers

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

What is focal length?

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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A student made the claim that a 4 gram paintball fired from a paintball gun at 90 m/s could have about the same kinetic energy as a 1 gram BB pellet fired from a BB gun at 180 m/s.

Do you agree or disagree with the student's claim? Use evidence and mathematical reasoning to support your response.

Answers

This question involves the concept of kinetic energy.

The student's claim is "right".

Kinetic Energy

The energy possessed by a body, by the virtue of its motion is called kinetic energy. Mathematically it is given by the following formula:

[tex]K.E =\frac{1}{2}mv^2[/tex]

where,

K.E = Kinetic energy m = massv = velocity

Therefore,

For the paintball:

[tex]K.E = \frac{1}{2}(4\ g)(90\ m/s)^2[/tex]

K.E = 16200 J

For the pellet:

[tex]K.E = \frac{1}{2}(1\ g)(180\ m/s)^2[/tex]

K.E = 16200 J

Hence, both paintball and pellet will have same kinetic energy. The student is right.

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Three 20.0 ohm resistors are
connected in parallel and attached to
a 5.00 V battery. How much current
flows out of the battery?

Answers

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

A 9-volt battery is connected to a 4-ohm resistor and a 5-ohm resistor as shown in the diagram above. How much current flows through the 4-ohm resistor?




1.0 A


1.8 B


2.3 C


4.0 D

Answers

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

Equivalent resistance of the circuit

The equivalent resistance of the circuit is determine as follows;

Rt = R1 + R2

Rt = 4 ohms + 5 ohms = 9 ohms

Current flowing in the 4 ohms resistor

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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Select the correct answer. kristina works out seven days a week. lately, she has been tired, and her body aches. if she is overtraining, which training principle should kristina consider before continuing her program? a. overload b. recovery c. transfer d. variation

Answers

Answer:

Select the correct answer. kristina works out seven days a week. lately, she has been tired, and her body aches. if she is overtraining, which training principle should kristina consider before continuing her program? a. overload b. recovery c. transfer d. variation

b recovery

Study the image.
The image shows the electric field lines between two charged plates.
Which statement would be true for these plates?
Select one:
A. The right plate is neutral.

B. The right plate is positively charged.

C. The left plate is positively charged.

D. The left plate is neutral.

Answers

C. the left plate is positively charged
when looking at these arrows imagine there is a positive electron at the beginning of the arrow. Since the electrons are going towards the plate to the right it is attracted to the negatively charged plate. These electrons want to get away from the positively charged plate because same charges repulse each other

Abdul, while driving to school, computes the average speed for his trip to be 20 km.h–1. On his return trip along the same route, there is less traffic and the average speed is 30 km.h–1. What is the average speed for Abdul’s trip?

Answers

Pretty sure it’s 25 km/h
(30 + 20) / 2 = 25 km/h

If you have a voltage of 120 volts entering your house and a light bulb with 0.75 amperes flowing through it, how many watts is your light bulb?
30 watts
120 watts
60 watts
90 watts

Answers

Answer:

90 watts

Explanation:

Formula for Power (using voltage and current) :

P = VIP = 120 V × 0.75 AP = 90 watts

Answer:

90 watts

Explanation:

Watts = volts x amperes

120X.75 = 90

The masses of two objects are 2 kg and 8 kg, respectively.If their kinetic energies are in 2:1 proportion, the ratio of their speeds is ___.
√2 :1
1:2
2√2 :1

Answers

Let's see

[tex]\\ \rm\Rrightarrow \dfrac{KE_1}{KE_2}=\dfrac{2}{1}[/tex]

[tex]\\ \rm\Rrightarrow \dfrac{0.5(2)v_1^2}{0.5(8v_2^2)}=\dfrac{2}{1}[/tex]

[tex]\\ \rm\Rrightarrow \dfrac{v_1^2}{4v_2^2}=\dfrac{2}{1}[/tex]

[tex]\\ \rm\Rrightarrow v_1^2=8v_2^2[/tex]

[tex]\\ \rm\Rrightarrow \dfrac{v_1^2}{v_2^2}=\dfrac{8}{1}[/tex]

[tex]\\ \rm\Rrightarrow \dfrac{v_1}{v_2}=\dfrac{2\sqrt{2}}{1}[/tex]

[tex]\\ \rm\Rrightarrow v_1:v_2=2\sqrt{2}:1[/tex]

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how much work is done on a small car if a 3000 N force is exerted to move it 75 m to the side of the road ?​

Answers

Answer:

Soln,

force=3000 N

distance=75 m

we know that,

work done= force × distance

= 3000× 75

= 225000 joule

A wave is sent down a tunnel where it travels and bounces of the far wall, returning to the sender. The wave travels at 4m/s and it takes 120 seconds to travel there and back. How deep is the cave?​

Answers

Answer:

100ft

Explanation:

Which form of precipitation is most likely to occur when the temperature in the clouds is below freezing, but the temperature in the air below is above freezing?

Hail
Rain
Sleet
Snow

Answers

the answer to this is HAIL

Answer:

Hail :) hope this helps

Explanation:

A mover pushes a 20 kg crate across a level floor with a force of 200 n, but
a the crate accelerates at a rate of only 7.5 m/ s2 because a friction force
opposes the crate's motion. what is the magnitude of this force of friction?
200 n
force of friction
a. 50 n
b. 15 n
c. 25 n
d. 100 n

Answers

The magnitude of the force of friction between the crate and floor is 50 N.

Magnitude of the force of friction

The magnitude of the force of friction is determined from Newton's second law of motion.

F - Ff = ma

Ff = F - ma

Ff = 200 - (20 x 7.5)

Ff = 50 N

Thus, the magnitude of the force of friction between the crate and floor is 50 N.

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A motor lets a 450.N crate drop at a constant 5.75m/s. What is the power output of the motor?

A motor lets a 450.N crate drop at a constant 5.75m/s. What is the power output of the motor?

78.3W

2590W

444W

456W

Answers

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

What is power?

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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The amount of electric energy consumed by a 60 watt lightbulb for 1 minute could lift a 10 newton object to a maximum vertical height of

Answers

Answer: physics are fake

Explanation:

if nominal gdp is 1800 and the money supply is 450, then what is velocity?

Answers

Answer:

Explanation:

answer: 4 velocity.

if nominal gdp is 1800 and the money supply is 450, then what is velocity?


4 velocity.

If the nominal GDP is 1800 and the money supply is 450, then the velocity of money would be 4.

The total value of goods and services generated in an economy during a given time period, usually a year, is referred to as nominal GDP and is not adjusted for inflation. It depicts what products and services are now selling on the market.

Given:

Nominal GDP, PQ = 1800

Money supply, M = 450

From equation of exchange:

MV = PQ

V = (PQ) ÷ M

V = (1800) ÷ (450)

V = 4

Hence, if the nominal GDP is 1800 and the money supply is 450, then the velocity of money would be 4.

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If you touch a conductor through which electricity flows with an insulator, will you receive a shock? Explain.

Answers

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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A glass prism can be used to show the dispersion of white light to form a spectrum.

a.Draw a diagram to show how a ray of white light is dispersed as it passes through a prism.

b.Which colour of light is most strongly dispersed (deflected) as it passes through the prism?
c.Explain why some colours of light are more strongly dispersed than others.
For each of the following statements, decide whether it is true or false.​

Answers

a) For Diagram refer to the attachment.

b) The colour that dispersed most is violet.

c) Every colour has its own wavelengths/ frequency. Different colours move with same speed in air / vaccum. But their speeds in refracting media like glass are different. Therefore, refractive index of the medium for different colours is different. Some gets strongly dispersed due to shorter wavelengths.

Explanation :

Dispersion of Light : The splitting up of a white light into different colours is called Dispersion of light. The light is made up of different colours. Each colour travels at its own speed inside a prism. Due to this different colours of light bend through different angles with respect to the incident ray , as they pass through a prism. The eed light bends the least while the violet the most. Thus, the rays of each colour emerge along different paths and thus becomes distinct.

Which two elements undergo fusion in the sun?​

Answers

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.

PLEASE HELP


Which of the following is a characteristic property of the alkaline earth
metals?
A. They are harder than alkali metals.
B. They are more reactive than alkali metals.
C. They all have 3 valence electrons.
D. They are all radioactive.

Answers

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


3. Assume that a sample decays with a given half-life. Will you be able to observe when the sample has completely decayed? Why or why not?

Answers

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

A taser sends about 1100 V through the human body, resulting in an average current of 2.5 mA. a) Determine the Power output of the taser. b) How much charge (C) flows per second? c) How many electrons flow through the body per second when the taser is deployed through someone's body?​

Answers

This question involves the concepts of current, power, and charge.

a) The power of taser is "2.75 watt".

b) The magnitude of charge flow per second "2.5 x 10⁻³ C/s".

c) Electrons flow per second is "1.56 x 10¹⁶ electrons/s".

a) Power

The power of the taser can be given by the following formula:

P = IV

where,

P = Power = ?I = current = 2.5 mA = 2.5 x 10⁻³ AV = potential difference = 1100 V

Therefore,

P = (2.5 x 10⁻³ A)(1100 V)

P = 2.75 Watt

b) Charge Flow per Second

The charge flow per second is equal to the current passing through taser.

[tex]\frac{q}{t}=I[/tex]

where,

[tex]\frac{q}{t}[/tex] = charge flow per second = ?I = current = 2.5 mA = 2.5 x 10⁻³ A

Therefore,

[tex]\frac{q}{t}=2.5\ x\ 10^{-3}\ C/s[/tex]

c) Electron Flow per Second

The electron flow per second is given by the following formula:

[tex]I = \frac{q}{t} = \frac{ne}{t}\\\\\frac{n}{t}=\frac{q}{te}[/tex]

where,

[tex]\frac{n}{t}[/tex] = electrons flow per second = ?e = charge on one electron = 1.6 x 10⁻¹⁹ C

Therefore,

[tex]\frac{n}{t}=\frac{2.5\ x\ 10^{-3}\ C/s}{1.6\ x\ 10^{-19}\ C}\\\\\frac{n}{t}=1.56\ x\ 10^{16}\ electrons/s[/tex]

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. A 6 ohm resistor is connected to a 15 volt battery.
a. What is the current in the circuit?
b. How much heat is produced in 10 minutes?

Answers

Answer:

2.5A , 22500 JOULE

Explanation:

Resistance (R)= 6 ohm

Voltage (V) = 15 volt

a)

Current (I) = ?

From ohm's law,

V=IR

15 = 6*I

I = 2.5 A

b)

time(t) = 10min = 600 second

heat energy (Q) = ?

from Joule's law of heating,

Q = I²*R*t

Q = 2.5² *6*600

Q = 22500 Joule

hence, heat energy produced is 22500 joule.

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