5. How does the existence of humans compare with Earth's age?

Answers

Answer 1

Answer:

Human activity has fundamentally changed our planet. We live on every continent and have directly affected at least 83% of the planet’s viable land surface. Our influence has impacted everything from the makeup of ecosystems to the geochemistry of Earth, from the atmosphere to the ocean. Many scientists define this time in the planet’s history by the scale of human influence, and label it as a new geological epoch called the Anthropocene.

Explanation:


Related Questions

An object that moves in uniform circular motion has a centripetal acceleration of 13 m/s^2 . If the radius of the motion is 0.02m, what is the frequency of motion?

Answers

Answer:

f = 3.97 Hz

Explanation:

Given that,

Centripetal acceleration, [tex]a=13\ m/s^2[/tex]

The radius of motion is 0.02 m

The formula for the centripetal acceleration is given by :

[tex]a=\dfrac{v^2}{r}\\\\v=\sqrt{ar} \\\\v=\sqrt{13\times 0.02} \\\\v=0.5\ m/s[/tex]

The speed of an object in a circular path is given by :

[tex]v=\dfrac{2\pi r}{t}[/tex]

t is time period

Also, f=1/t (f is frequency)

[tex]f=\dfrac{v}{2\pi r}\\\\f=\dfrac{0.5}{2\pi \times 0.02}\\\\f=3.97\ Hz[/tex]

Hence, the frequency of motion s 3.97 Hz.

The frequency of the motion is 4.1 Hz.

Linear velocity?

The linear velocity of the of the object is calculated as follows;

[tex]a = \frac{v^2}{r} \\\\v^2 = ar\\\\v = \sqrt{ar} \\\\v = \sqrt{13 \times 0.02} \\\\v = 0.51 \ m/s[/tex]

Angular speed of the object

The angular speed of the object is calculated as follows;

[tex]\omega =\frac{v}{r} \\\\\omega = \frac{0.51}{0.02} \\\\\omega = 25.5 \ rad/s[/tex]

Frequency of motion

The frequency of the motion is calculated as follows;

[tex]\omega = 2\pi f\\\\f = \frac{\omega }{2\pi} \\\\f = \frac{25.5}{2\pi } \\\\f = 4.1 \ Hz[/tex]

Thus, the frequency of the motion is 4.1 Hz.

Learn more about frequency of the circular motion here: https://brainly.com/question/20481765

find the fundamental units involved in derived units
newton
watt
joule
pascal
cubic meter ​

Answers

9ycy8c8t 7f fixfuozofuxt8lsrupsurpaurae6pUeoUe6eoUeFipzuroz6d0, 7d0z6e0z7e0zurpz6e0z

Explanation:

force newton N - m·kg·s-2

pressure, stress pascal Pa N/m2 m-1·kg·s-2

energy, work, quantity of heat joule J N·m m2·kg·s-2

power, radiant flux watt W J/s m2·kg·s-3

volume cubic meter m3

True or False. A projectile is an object that once set in motion, continues in motion by its own inertia.

Answers

The answer is true.
It’s true hope this helps!!

A 7.50 kg bowling ball has 70.4
kg•m/s of momentum. What is its
velocity?

Answers

Answer:

9.39 m/s

Explanation:

The velocity of the bowling ball can be found by using the formula

[tex]v = \frac{p}{m} \\ [/tex]

p is the momentum

m is the mass

From the question we have

[tex]v = \frac{70.4}{7.5} \\ = 9.38666666..[/tex]

We have the final answer as

9.39 m/s

Hope this helps you

A spaceship of mass mm circles a planet of mass M in an orbit of radius R. How much energy is required to transfer the spaceship to a circular orbit of radius 3R?

Answers

Answer:

ΔE = GmM/3R

Explanation:

The absolute potential energy of an object in a planet's field is given as:

E = -GmM/2r

where,

E = Potential Energy

G = Universal Gravitational Constant

m = mass of spaceship

M = Mass of Planet

r = distance from surface of planet

Therefore, for initial state:

E = E₁ and r = R

E₁ = - GmM/2R

and for final state:

E = E₂ and r = 3R

E₂ = - GmM/6R

So, the required energy will be:

ΔE = E₂ - E₁ = - GmM/6R + GmM/2R

ΔE = GmM(- 1/6R + 1/2R)

ΔE = GmM/3R

<

Question

An airplane flies eastward and always accelerates at a constant rate. At one position along its path, it has a velocity of

32.7 m/s. It then flies a further distance of 44500 m, and afterwards, its velocity is 50.3 m/s. Find the

airplane's acceleration

acceleration:

.016m/s2

Calculate how much time clapses while the airplane covers those 44500 m

about us

Careers

privacy policy

Terms of Use

contact us

help

49 ENG

1:45 PM

9/17/2020

Answers

Answer:

Explanation:

initial velocity u = 32.7 m /s

final velocity v = 50.3 m /s

displacement s = 44500 m

acceleration a = ?

v² = u² + 2 a s

50.3² = 32.7² + 2 x a x 44500

2530.09 = 1069.29 + 89000a

a .016 m /s²

time taken t = ?

v = u + at

50.3 = 32.7 + .016 t

t = 1100 s

Two tiny conducting spheres are identical and carry charges of -20μC and +50μC. They are separeted by a distance of 2.50cm. (a) what is the magnitude of the force that each sphere each sphere experience, and is the force attractive or repulsive ? (b) The spheres are brought into contact and then separated toa distance of 2.50cm. Determine the magnitude of the force that each sphere now experiences, and state whether the force is attractive or repulsive.

Answers

Answer:

[tex]14400\ \text{N}[/tex], Attractive

[tex]3240\ \text{N}[/tex], Repulsive

Explanation:

[tex]q_1[/tex] = -20 μC

[tex]q_2[/tex] = 50 μC

r = Distance between the charges = 2.5 cm

k = Coulomb constant = [tex]9\times 10^9\ \text{Nm}^2/\text{C}^2[/tex]

Electrical force is given by

[tex]F=\dfrac{kq_1q_2}{r^2}\\\Rightarrow F=\dfrac{9\times 10^9\times (-20\times 10^{-6})\times (50\times 10^{-6})}{(2.5\times10^{-2})^2}\\\Rightarrow F=-14400\ \text{N}[/tex]

The magnitude of force each sphere will experience is [tex]14400\ \text{N}[/tex]

Since the charges have opposite charges they will attract each other.

Now the charges are brought into contact with each other so the resultant charge will be

[tex]q=\dfrac{q_1+q_2}{2}\\\Rightarrow q=\dfrac{-20+50}{2}\\\Rightarrow q=15\ \mu\text{C}[/tex]

[tex]F=\dfrac{kq^2}{r^2}\\\Rightarrow F=\dfrac{9\times 10^9\times (15\times 10^{-6})^2}{(2.5\times 10^{-2})^2}\\\Rightarrow F=3240\ \text{N}[/tex]

The magntude of the force the spheres experience will be [tex]3240\ \text{N}[/tex]

The spheres have the same charge now so they will repel each other.

a vertical solid steel post 29cm in diameter and 2.0m long is required to support a load of 8200kg, ignore the weight of the post. determine the stress in the post​

Answers

Answer:

The stress is  [tex]\sigma = 1.218*10^{6} \ N/m^2[/tex]

Explanation:

From the question we are told that

   The diameter of the post is  [tex]d = 29 \ cm = 0.29 \ m[/tex]

   The length is [tex]L = 2.0 \ m[/tex]

    The weight of the loading mass

Generally  the  radius of the post is mathematically represented as

     [tex]r = \frac{0.29}{2}[/tex]

=>   [tex]r = 0.145 \ m[/tex]

Generally the area of the post is  

       [tex]A = \pi r^2[/tex]

=>     [tex]A = 3.14 * 0.145 ^2[/tex]

=>     [tex]A = 0.066 \ m^2[/tex]

Generally the weight exerted by the load is mathematically represented as

        [tex]F = m * g[/tex]

=>      [tex]F = 8200 * 9.8[/tex]

=>      [tex]F = 80360 \ N[/tex]

Generally the stress is mathematically represented as

         [tex]\sigma = \frac{F}{A}[/tex]

=>      [tex]\sigma = \frac{80360 }{0.066}[/tex]

=>      [tex]\sigma = 1.218*10^{6} \ N/m^2[/tex]

Which environment is least likely to support protists
A soil
B open ocean
C shallow pod
D organisms blood

Answers

Answer:

A: Soil

Explanation:

Protists need a moist environment to survive, and shallow ponds, oceans, and blood is all moist. So, the answer would be the soil, because that is the least moist environment out of these options.

An electromagnet needs a magnetic metal core. To produce a magnetic field,
what else is required?

A second metal core?
A solenoid with current or no current running through it? Or a permanent magnet?

Answers

A second metal core i think

Answer:solenoid with current running through it

Explanation:just took the test

Why are the coral reefs suffering? (site 2) explain

Answers

Answer:

bcuz ov yo fat mamma

Explanation:

Answer:

Water pollution

Explanation:

A displacement vector with a magnitude of 20. meters could have perpendicular components with magnitudes of A. 10. m and 10. m B. 12 m and 8.0 m 12 m and 16 m D. 16 m and 8.0 m​

Answers

Answer:10.m and 10. M

Explanation:

A displacement vector with a magnitude of 20. m could have perpendicular components with magnitudes of C. 12 m and 16 m.

A displacement vector with a magnitude of 20. meters can be decomposed in 2 perpendicular components.

They would form a right triangle, in which the displacement vector would be the hypotenuse (a) and the components would be the legs (b, c).

Given the magnitude of the legs, we can calculate the magnitude of the hypotenuse using the Pythagorean theorem.

[tex]c = \sqrt{a^{2} + b^{2} }[/tex]

Let's use this formula to calculate the displacement vector for each pair of legs.

A. 10. m and 10. m

[tex]c = \sqrt{a^{2} + b^{2} } = \sqrt{(10.m)^{2} + (10.m)^{2} }= 14.1m[/tex]

B. 12 m and 8.0 m

[tex]c = \sqrt{a^{2} + b^{2} } = \sqrt{(12m)^{2} + (8.0m)^{2} }= 14.4m[/tex]

C. 12 m and 16 m

[tex]c = \sqrt{a^{2} + b^{2} } = \sqrt{(12m)^{2} + (16m)^{2} }= 20m[/tex]

D. 16 m and 8.0 m​

[tex]c = \sqrt{a^{2} + b^{2} } = \sqrt{(16m)^{2} + (8.0m)^{2} }= 17.9m[/tex]

A displacement vector with a magnitude of 20. m could have perpendicular components with magnitudes of C. 12 m and 16 m.

Learn more: https://brainly.com/question/16426393

1000 kg car takes travels on a circular track having radius 100 m with speed 10 m/s. What is the direction of the acceleration of the car? *
A- outside track, and normal to track
B- towards the center and normal to the track
C- up
D- down

Answers

Answer:

B.

Explanation:

when is thermal equilibrium achived between two identical objects



need help ASAP

Answers

Answer: When two objects in contact with each other are at different temperatures, they are said to be in thermal equilibrium.

Explanation: . When two objects not in contact with each other are at the same pressure, they are said to be in thermal equilibrium.

A kangaroo jumps straight up to a vertical height of 1.45 m. How long was it in the air before returning to Earth?

Answers

Answer:

1.08 s

Explanation:

From the question given above, the following data were obtained:

Height (h) reached = 1.45 m

Time of flight (T) =?

Next, we shall determine the time taken for the kangaroo to return from the height of 1.45 m. This can be obtained as follow:

Height (h) = 1.45 m

Acceleration due to gravity (g) = 9.8 m/s²

Time (t) =?

h = ½gt²

1.45 = ½ × 9.8 × t²

1.45 = 4.9 × t²

Divide both side by 4.9

t² = 1.45/4.9

Take the square root of both side

t = √(1.45/4.9)

t = 0.54 s

Note: the time taken to fall from the height(1.45m) is the same as the time taken for the kangaroo to get to the height(1.45 m).

Finally, we shall determine the total time spent by the kangaroo before returning to the earth. This can be obtained as follow:

Time (t) taken to reach the height = 0.54 s

Time of flight (T) =?

T = 2t

T = 2 × 0.54

T = 1.08 s

Therefore, it will take the kangaroo 1.08 s to return to the earth.

3. Sarah drops a 10.0 kg objed from a 200 m high bridge over a river. a) What work is done by the objec as a result of its fall? ​

Answers

work done = force x distance
10kg is 98.1 newtons
98.1x200=19620
i’m not sure though sorry if this is wrong :)

Which type of mass movement is likely to result in considerable property damage, but rarely causes loss of life? a. debris avalanche b. rock fall c. mudflow d. creep

Answers

Answer:

The correct answer is D. Creep.

Explanation:

Ground creep is a slow downward movement of a hill or mountain slope without the formation of demolition forms. The decisive factor for this is the continuous flow of movement of the soil.

The main driver of collapse is the movement of the surface layer particles during expansion in a direction perpendicular to the slope, followed by vertical collapse on contraction. The visible effect of the collapsing is the inclination of fences and poles, as well as trees that grow out of the ground towards the slope and have trunks curved vertically, in more extreme cases it may be cracks on the walls of buildings.

What specific changes in two climate variables are expected to lead to major decreases in soil moisture southern Africa and the Mediterranean region?

Answers

Answer:

Less precipitation, droughts9: How might agriculture in southern Europe change by the end of the century if conditions follow the RCP8.

Explanation:

Precipitation and droughts are the specific changes in two climate variables that are expected to lead to major decreases in soil moisture.

What is drought?

Drought is defined as a period of protracted water scarcity, whether it is due to atmospheric surface water, or groundwater constraints.

Droughts can last months or years, although they can be proclaimed in as little as 15 days.

It has the potential to have a significant influence on the afflicted region's ecology and agriculture as well as harm the local economy.

Precipitation and droughts are the specific changes in two climate variables that are expected to lead to major decreases in soil moisture in southern Africa and the Mediterranean region.

Hence Precipitation and droughts are the specific changes in two climate variables.

To learn more about the drought refer to the link;

https://brainly.com/question/26693108

You are lifting a 10 kg block straight up at a constant speed of 10 m/s. How much force are you exerting on the block?

Answers

Answer:

The force exerted is [tex]F = 100 \ N[/tex]

Explanation:

From the question we are told that

   The mass of the block is [tex]m_b = 10 \ kg[/tex]

    The speed is  [tex]v = 10 \ m/s[/tex]

Generally the force exerted to lift the object at constant speed is equivalent to the wight of the ball, this is mathematically represented as

       [tex]F = m * g[/tex]      Here  [tex]g = 10 \ m/s^2[/tex]

=>    [tex]F = 10 * 10[/tex]

=>    [tex]F = 100 \ N[/tex]

The force are you exerting on the block when the block is lifting straight up with constant speed is 98 N and this can be determined by using the given data.

Given :

You are lifting a 10 kg block straight up at a constant speed of 10 m/s.

The following steps can be used in order to determine the force are you exerting on the block:

Step 1 - According to the given data, the block is lifting straight up at a constant speed. So, the acceleration is zero.

Step 2 - So, the only force exerted on the block is the weight of the block.

Step 3 - So, the force are you exerting on the block is given by:

F = mg

F = 10 [tex]\times[/tex] 9.8

F = 98 N

For more information, refer to the link given below:

https://brainly.com/question/2996858

Question 1 of 5
In which way are electromagnetic waves different from mechanical waves?

Answers

Answer:

Electromagnetic waves differ from mechanical waves in that they do not require a medium to propagate. This means that electromagnetic waves can travel not only through air and solid materials, but also through the vacuum of space.

Explanation:

Answer:

In which way are electromagnetic waves different from mechanical waves?Electromagnetic waves can travel through empty space

Explanation:

I took A P E X Quiz.

The spring constant, k, for a 22cm spring is 50N/m. A force is used to stretch the spring and when it is measured again it is 32cm long. Work out the size of this force

Answers

Answer:

5N

Explanation:

Given parameters:

Original length = 22cm

Spring constant, K  = 50N/m

New length = 32cm

Unknown

Force applied  = ?

Solution:

The force applied on a spring can be derived using the expression below;

   Force  = KE

 k is the spring constant

 E is the extension

  extension = new length - original length

  extension  = 32cm  - 22cm  = 10cm

convert the extension from cm to m;  

   100cm  = 1m;

    10cm will give 0.1m

So;

  Force  = 50N/m x 0.1m  = 5N

A 0.12-m-radius grinding wheel takes 5.5 s to speed up from 2.0 rad/s to 11.0 rad/s. What is the wheel's average angular acceleration?

Answers

Answer:

0.56rad/s²

Explanation:

Using the equation of motion

wf = wi + αt

wf is the final angular velocity

wi is the initial angular velocity

α is the angular acceleration

t is the time

Given

wf = 11.0rad/s

wi =2.0rad/s

t = 5.5secs

Substitute into the formula and get α

11.0 = 2.0+5α

11.0-2.0 = 5α

9.0 = 5α

α = 5/9.0

α ≈ 0.56rad/s²

Hence the wheel's average angular acceleration is 0.56rad/s²

The wheel's average angular acceleration is equal to 1.64 [tex]rad/s^2[/tex].

Given the following data:

Radius = 0.12 meterTime = 5.5 secondsInitial angular velocity = 2.0 rad/sFinal angular velocity = 11.0 rad/s

To determine the wheel's average angular acceleration, we would apply the first equation of kinematics:

Mathematically, the angular acceleration of an object is given by the formula:

[tex]\alpha = \frac{\omega_f - \omega_i}{t}[/tex]

Where:

[tex]\omega_i[/tex] is the initial angular velocity.[tex]\omega_f[/tex] is the final angular velocity.t is the time.

Substituting the given parameters into the formula, we have;

[tex]\alpha =\frac{11.0\;-\;2.0}{5.5} \\\\\alpha =\frac{9.0}{5.5}[/tex]

Angular acceleration = 1.64 [tex]rad/s^2[/tex]

Read more: https://brainly.com/question/8898885

When a mass of a cart is 10 kg, and an applied force is 5 N, The acceleration of the cart is

5.0 m/s2
2.0 m/s2
0.5 m/s2
0.2 m/s2

Answers

Answer:

0.5 m/s2

Explanation:

F = ma

5 = 10a

a = 5/10

a =0.5

A locomotive creates a
59,400 N force, which creates
an acceleration of 0.145 m/s.
What is the mass of the
locomotive?
Unit=kg

Answers

Answer:

410,000 kg

Explanation:

Use Newton's second law

F = ma

m = F/a

m = 59,400 N/(.145 m/s) = 410,000 kg

A 6.0-kilogram cart initially traveling at 4.0 meters per second east accelerates uniformly at 0.50 meter per second squared east for 3.0 seconds. What is the speed of the cart at the end of this 3.0 second interval? A. 1.5 m/s B. 5.5 m/s G. 3.0 m/s D. 7.0 m/s​

Answers

Answer: 5.5m/s

Explanation:

vf=vi+at

vf= 4.0m/s + (0.50m/s^2)(3.0s)

The speed of the cart at the end of this 3.0 second interval is 5.5 meter per seconds.

Given the following data:

Initial velocity = 4 m/sMass of cart = 6 KgAcceleration = 0.5 [tex]m/s^2[/tex]Time = 3 seconds

To find the speed of the cart at the end of this 3.0 second interval, we would use the first equation of motion;

[tex]V = U + at[/tex]

Where:

U is the initial velocity.V is the final velocity. a is the acceleration. t is the time measured in seconds.

Substituting the given parameters into the formula, we have;

[tex]V = 4 + 0.5(3)\\\\V = 4 + 1.5[/tex]

Final velocity, V = 5.5 m/s.

Therefore, the speed of the cart at the end of this 3.0 second interval is 5.5 meter per seconds.

Read more: https://brainly.com/question/8898885

In a simulation on earth, an astronaut in his space suit climbs up a vertical ladder. On the moon, the same astronaut makes the same climb. In which case does the gravitational potential energy of the astronaut change by a greater amount?

Answers

Answer:

Gravitational potential energy of the astronaut will change by a greater amount on the earth

Explanation:

Gravitational potential energy is expressed by the formula;

GPE = mgh

This means that the gravitational potential energy is directly proportional to the gravity(g)

Now, from constant values, gravity of moon is 1.62 m/s² while gravity of the earth is 9.81 m/s².

This means that if we plug in the values of g on the earth and g on the moon, the potential energy on the earth would be greater than that of the moon

Thus, gravitational potential energy of the astronaut will change by a greater amount on the earth

The following is the longitudinal characteristic equation for an F-89 flying at 20,000 feet at Mach 0.638. The Short Period natural frequency is _____.

Answers

Answer:

hello your question is incomplete  attached below is the missing part  

answer : short period oscillations frequency  = 0.063 rad / sec

              phugoid oscillations natural frequency ( [tex]w_{np}[/tex] ) = 4.27 rad/sec

Explanation:

first we have to state the general form of the equation

= [tex]( S^2 + 2\alpha _{p} w_{np} S + w^{2} _{np} ) (S^{2} + 2\alpha _{s} w_{ns}S + w^{2} _{ns} ) = 0[/tex]

where :

[tex]w_{np} = Natural frequency of plugiod oscillation[/tex]

[tex]\alpha _{p} = damping ratio of plugiod oscilations[/tex]

comparing the general form with the given equation

[tex]w^{2} _{np}[/tex]  = 18.2329

[tex]w^{2} _{ns} = 0.003969[/tex]

hence the short period oscillation frequency ( [tex]w_{ns}[/tex] ) =  0.063 rad/sec

phugoid oscillations natural frequency ( [tex]w_{np}[/tex] ) = 4.27 rad/sec

The speed of a space shuttle is 10 / express this in /�

Answers

Answer:

268.22m/s

Explanation:

Given;

    10mile/min to m/s

We need to convert between the two units;

    1 mile  = 1609.34m

     60s  = 1min

Now;

    10 x [tex]\frac{mile}{min}[/tex] x [tex]\frac{1min}{60s}[/tex] x [tex]\frac{1609.34m}{1mile}[/tex]

  = 268.22m/s

A motorcycle moving at a constant velcoity suddenly accelerates at a rate of 4.0 m/s/s to a speed of 35 m/s in 5.0 s. What was the initial speed of the motorcycle?

Answers

Answer:

15 m/s

Explanation:

v = u+ at

35 = u + 20

35-20 = u

u= 15 m/s

1. When asteroids collided some of the broken materials fall into Earth's orbit. What do
astronomers call the debris when it hits planet Earth?

Answers

Answer:

meteoroids

Explanation:

when an asteroid (or really anything else) falls to earth, it is called a meteoroid

Other Questions
How something works is related to its structure PLZZ ANSWER THE QUESTION Use the evidence of these ammonite index fossils, what can we say about these twogeologic layers?They were laid down around the same timeSandstone is older than the shaleShale is older than the sandstone Since they are from different locations, unless we can radiometric Lee date them, we cannot distinguish anything between the two How has Sowers created change? How might she inspire others to create change? In what ways did the Enlightenment influence ideas that led to the American Revolution? (WHII5.e) aNew ideas about government led to the colonists questioning British rule bThe salons influences the French and Indian War cThe heliocentric theory caused unrest among the colonists dNew ideas about government spurred colonists to become more loyal to the British monarchy el nmero de llegadas al servicio de urgencias de un hospital es de 2 cada 15 min. Si se supone queel numero de llegadas se distribuye en un modelo de Poisson, se pretende calcular la probabilidadde que en los prximos 15 min se produzcan 4 llegadas.Ayuda por favor, es urgente. if you want brainiest than come herego to remind.com then log in as student then put the class code: c26kda4 How many valence electrons are found in P3- ? 37 % of $2927 is what yesterday at football practice, Han made 12 of his field goal attempts. Today he made 75% as many as he did yesterday. How many attempts did han make today? Convert as indicated.108 ounces to pounds What was the main problem with the government of the Confederate States ofAmerica?a) There was a lot of tension among the statesb) States couldn't agree on taxesc) The nature of a confederation doesn't promote unityd) The states couldn't agree on the use of slaves in the war effort Joe has 6 marbles. Joe and Kay have 11 marbles. Kay and Sara have 7 marbles. How many marbles does Sara have? Anita is surveying students in her classroom about their favourite foods. Her survey results so far are shown below. Use fractions to answer the question. What fraction of the students prefers either ice cream or pizza?Type of Food: Fraction of Students Who Prefer the Food:Fruit 1/12Ice cream 1/3Pizza 1/4Other ? If IN=2x+10 and AT=26, find x.A.) 12B.) 10C.) 6 D.) 8 how do you turn a vertical image to a horizontal image? Modern artists have rejected Romanticism and are more influenced by Classical works.TrueFalse help with this question please How do NGOs help in a humanitarian crisis? Researchers are interested in estimating the percentage of Americans who will get a flu shot this year. How many Americans should be surveyed to be 80% confident that the sample proportion of Americans who will get a flu shot this year is within 0.100 of the population proportion Assume we have a prior estimate of 45%. Round your z critical value to four decimal places.