We would have to search at least 5,000,000,000 (5 billion) stars before we would expect to hear a signal.
To find out the number of stars that we will need to search to find a signal, we need to use the following formula:
total of stars/civilizations500,000,000,000 (500 billion) stars / 100 civilization = 5,000,000,000 (5 billion)
This shows it is expected to find a civilization every 5 billion stars, and therefore it is necessary to search at least 5 billion stars before hearing a signal from any civilization.
Note: This question is incomplete; here is the complete question.
On average, how many stars would we have to search before we would expect to hear a signal? Assume there are 500 billion stars in the galaxy.
Assuming 100 civilizations existed.
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12. Since the Clean Air Act was passed in 1970, why is the air still not clean?
Answer:
Congress designed the Clean Air Act to protect public health and welfare from different types of air pollution caused by a diverse array of pollution sources.
Explanation:
Find the distance traveled in one back-and-forth swing by the weight of a 12 in. Pendulum that swings through a 75 degree angle.
The distance traveled by pendulum, in one back-and-forth swing is 75.75 inches.
The period of pendulum can be calculated by
[tex]T = 2\pi \sqrt {\dfrac Lg}[/tex]
Where,
[tex]T[/tex] - period
[tex]L[/tex] - length = 12 inches
[tex]g[/tex]- gravitational acceleration = [tex]\bold {9.8\rm \ m/s^2}[/tex]
Put the values,
[tex]T = 2\pi \sqrt {\dfrac {12}{9.8}}\\\\T = 2 \times 3.14 \times \sqrt {0.122}\\\\T = 2.191[/tex]
Now, the angular displacement of the pendulum can be calculated by,
[tex]\theta = A\times\rm \ cos(\omega T)[/tex]
Where,
[tex]A[/tex]- amplitude
[tex]\theta[/tex] - angle = [tex]75^o[/tex]
[tex]\omega[/tex] - angular displacement = [tex]2\pi/T[/tex] = 2.866 m
Put the values and calculate for [tex]\omega[/tex],
[tex]75 = A\times{\rm \ cos}(2.866\times 2.191)\\\\75 =A \times cos\ 6.26\\\\A =\dfrac {75}{0.99}\\\\A = 75.75 \rm \ inches[/tex]
Therefore, the distance traveled by pendulum, in one back-and-forth swing is 75.75 inches.
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Energy stores in food would be considered what
Answer:
Energy stored in food is consider as carbohydrate,protein,fats,etc.
1. Taking accurate measurements of small values using the ‘measure many and average’ method.
Each oscillation takes a small amount of time, and your reaction time is about 0.1 seconds. This means too much of the time you measure is your reaction time. Find out the percentage error with this calculation;
a. ((reaction time)⁄(time for one oscillation))x100=% error
b. To reduce the percentage error, time for ten oscillations.
c. Take the average time by dividing your answer by ten.
d. Your reaction time is still the same, 0.1 s. Find out the new percentage error with this calculation;
Answer:
i need free answers here
Explanation:
a race car is traveling at a speed of 80.0m/s on a circular race track of radius 450m what is the centripetal acceleration
Answer:
The answer of this question is =1.258*10-4
what are the ending materials produced from cell respiration
Answer:
The products of cellular respiration are carbon dioxide and water
Explanation:
Calculate the Work done if the force is 2000 Newtons
and the distance is 5 km.
Answer:
10 million joules or 10,000 KJ
Explanation:
Work= Force x Displacement
convert 5km into meters -5km=5000m
W= 2000N x 5000m
w=10,000,000 Joules
or 10,000KJ
A car moving at 60 mph slams on its brakes to stop before hitting a deer. Another identical car traveling at 60 mph slows to a stop at a stop sign. Who experiences the greatest impulse during the stop
Happy Holidays!
Recall that:
Impulse = Change in Momentum = mass × change in velocity
Since both cars are identical and have the same initial velocity of 60 mph, them breaking to a stop means that they both experience the same change in velocity.
Thus, both of the cars' impulses are equal.
if you immerse an object into a known mass of water, the measured mass of the water will _____, and will be equal to the mass of the water displaced by the immersed object.
Answer: decrease
Explanation: it does
A baseball player at practice is pushing a tackling dummy across the field. He initially has to push the 130 kg dummy with 600 Newton’s of force to get it to start moving and maintain a force of 475 to keep it moving at a steady state. What are the coefficient of friction static and kinetic with the dummy on the ground
.
Answer:
Static= 600/(130*9.8)=0.47
Kinetic=475/(130*9.8)=0.37
Two 3.0g bullets are fired with speeds of 40.0 m/s
and 80.0 m/s, respectively. What are their kinetic
energies? Which bullet has more kinetic energy? What is the ratio of their kinetic energies?
[tex] = \sf \frac{1}{2} m {v}^{2} [/tex]
Kinetic energy of the 1st bullet [tex] \sf = \frac{1}{2} \times m1 \times {(v1)}^{2} \\ \sf= \frac{1}{2} \times 0.003 \times {(40)}^{2}J \\ \sf = \frac{1}{2} \times 0.003 \times 1600J \\ \sf = 2.4J[/tex]Kinetic energy of the 2nd bullet [tex] \sf = \frac{1}{2} \times m2 \times {(v2)}^{2} \\ \sf= \frac{1}{2} \times 0.003 \times {(80)}^{2}J \\ \sf = \frac{1}{2} \times 0.003 \times 6400J \\ \sf = 9.6J[/tex] So, the 2nd bullet which has greater velocity has more kinetic energy.Therefore, the ratio of their kinetic energies[tex] \sf = \frac{2.4J}{9.6J} \\ \sf= \frac{24}{96} = \frac{1}{4} \\ \sf = 1 : 4[/tex]
Answer:
The kinetic energies of the bullets are 2.4 J and 9.6 J.
The bullet having greater velocity has more kinetic energy.
The ratio of their kinetic energies is 1 : 4.
Hope you could get an idea from here
Doubt clarification - use comment section.
The kinetic energy of the two bullets are 2.4 J and 9.6 J respectively.
The ratio of the kinetic energy of the bullets is 1:4.
What is kinetic energy?The kinetic energy of an object is the energy possessed by the object due to its motion.
The kinetic energy of the two bullets is calculated as follows;
[tex]K.E_1 = \frac{1}{2} \times 0.003 \times 40^2 = 2.4 \ J\\\\K.E_2 = \frac{1}{2} \times 0.003 \times 80^2 = 9.6 \ J[/tex]
Ratio of the kinetic energy of the bullets is calculated as follows;
[tex]K.E_1 : K.E_2 = 2.4: 9.6 \ = \ 1: 4[/tex]
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A stone is thrown horizontally from the top of an inclined plane (angle of inclination θ). How would I find the initial speed of the stone if it hit the plane a distance L down the slope from the point of launch?
Answer:
S = V t where S is the horizontal distance traveled
1/2 g t^2 = H where H is the vertical distance traveled
t^2 = 2 H / g
V^2 = S^2 / t^2 = S^2 g / (2 H) combining equations
tan theta = H / S
V^2 = S g / (2 tan theta)
Using S = L cos theta
V^2 = L g cos theta / (2 tan theta)
Giving V in terms of L and theta
1. How much energy is needed just to melt 0.56kg of ice at 0◦ C?
2. How much energy is needed just to boil 5kg of water at 100◦ C?
3. What is the specific heat of metal if its mass is 27 g and it requires 420 J of heat energy to
increase its temperature from 25°C to 50°C?
please help me out I dont have much time
Answer:
This will require 266.9 of heat energy.
Explanation:
To calculate the energy required to raise the temperature of any given substance, here's what you require:The mass of the material, m The temperature change that occurs, ΔT The specific heat capacity of the material,
c
(which you can look up). This is the amount of heat required to raise 1 gram of that substance by 1°C.
Here is a source of values of
c for different substances:
Once you have all that, this is the equation:
Q=m×c×ΔT(Q is usually used to symbolize that heat required in a case like this.)For water, the value of c is 4.186g°C So, Q=750×4.186×85=266=858=266.858
How many neutrons are in an atom of Carbon-13 or (613C)?
Answer: 6 OR 7
Explanation:
A well chosen lifetime activity is something that should hold a person's interest for a long time.
Please select the best answer from the choices provided.
T
F
Answer:
true
Explanation:
as long as you are interested, you are happy
Since lifetime activities are done for a lifetime, it is true that a well chosen lifetime activity is something that should hold a person's interest for a long time.
What is a lifetime activity?A lifetime activity is an activity which an individual decides to do for a lifetime.
A lifetime activity should be able to hold a person's interest for a long time, else it could lead to frustration.
Some lifetime activities include:
choice of careersmarriage family relationshipsTherefore, it is true that a well chosen lifetime activity is something that should hold a person's interest for a long time.
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Which are the products in the equation CH3SH + 4O2 → CO2 + SO2 +2H2O? Check all that apply.
Answer:
ch3sh + 4O2 are the products
The gravitational force on Mars is about 38% of Earth. What would a cat weighing 15 pounds on Earth weigh on Mars?
Answer: 5.7
Explanation: 38% of 15.
The weight we experience ourselves and the ability to stand in the ground is due to the gravitational pull of earth. If this pull is lower we feel weight loss. So the cat will have a weight of 5.7 pounds or 2.58 kg in mars where the gravitation is about 38% of earth.
What is gravitational force?Gravitational force is a kind force by which a body attracts other objects into its centre of mass. Earth have strong gravitational effect on objects and thus we are all standing on the surface and everything falling from a height hits the ground.
As the mass of the object increases, gravitational effect also increases. The weight experienced by a body is the product of its mass and gravity. Thus massive body have greater weight.
Our mass is constant everywhere but weight will change according a change in gravity. Mars have only 38% of gravity of earth. Thus the cat weighing 15 pounds on earth will loss its weight in mars by 38%.
Thus, 15 × 38/100= 5.7 pounds will be the weight of the cat in mars.
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What is science notation
Answer:
Scientific notation is the way that scientists easily handle very large numbers or very small numbers. For example, instead of writing 0.0000000056, we write 5.6 x 10-9. So, how does this work? We can think of 5.6 x 10-9 as the product of two numbers: 5.6 (the digit term) and 10-9 (the exponential term).
Explanation:
A car drives 84 meters forward. It's displacement and distance would be the same?
Answer:
Yes.
Explanation:
Displacement is a vector quantity, meaning it has to be a straight graph jointing from starting point to final point and has a direction as well as magnitude and it can also be negative as well as positive and zero.
Displacement is also changes in position (points) of distance. A distance is scalar quantity meaning it only has magnitude and does not have direction. Since distance is scalar quantity, it cannot be negative. Also graph of distance can be a curve graph or any graph.
So when does displacement equal to distance? If an object is moving in straight path or line in one/fixed direction, both displacement and distance are same.
Because if a distance is a straight path and the displacement is simply a straight line (or ray) jointing from starting point to end point, both distance and displacement are both straight path or rays. Since distance and displacement have same graph, we can conclude that both are same in values.
If we go by calculus, given x = 2t as example of straight graph where x stands for position and t stands for time. We can find the displacement from b to a by using the following formulas:
Displacement
[tex]\displaystyle \large{s=\int\limits^b_a {v} \, dt}[/tex]
Distance
[tex]\displaystyle \large{l=\int\limits^b_a {|v|} \, dt}[/tex]
v stands for velocity which we can find from:
Velocity
[tex]\displaystyle \large{v=\frac{dx}{dt}}[/tex]
If you have learnt calculus, first, differentiate x = 2t with respect to t.
[tex]\displaystyle \large{v=2}[/tex]
Then substitute v = 2 in s and l to find find if both displacement and distance are equal in straight path.
Displacement
[tex]\displaystyle \large{s=\int\limits^b_a {2} \, dt}\\\displaystyle \large{s=[2t]\limits^b_a}\\\displaystyle \large{s=2b-2a = 2(b-a)}[/tex]
Distance
[tex]\displaystyle \large{l=\int\limits^b_a {|2|} \, dt}\\\displaystyle \large{l=\int\limits^b_a {2} \, dt}\\\displaystyle \large{l=[2t]\limits^b_a}\\\displaystyle \large{l=2b-2a=2(b-a)}[/tex]
Since both displacement and distance are equal when integrating on straight graph, we can conclude that an object moving in straight fixed point has same distance and displacement.
In a game of pool, a cue ball rolls without slipping toward the stationary eight ball with a momentum of 0.23 kg. After the two balls collide, the final momentum of the cue ball is 0.01 kg. what is the magnitude of the final momentum of the eight ball
This question involves the concepts of the law of conservation of momentum.
The magnitude of the final momentum of the eight ball is "0.22 N.s".
According to the law of conservation of momentum:
[tex]P_{i1}+P_{i2}=P_{f1}+P_{f2}[/tex]
where,
[tex]P_{i1}[/tex] = initial momentum of the cue ball = 0.23 N.s
[tex]P_{i2}[/tex] = initial momentum of the eight ball = 0 N.s (since ball is initially at rest)
[tex]P_{f1}[/tex] = final momentum of the cue ball = 0.01 N.s
[tex]P_{f2}[/tex] = final momentum of the eight ball = ?
Therefore,
[tex]0.23\ N.s + 0\N.s = 0.01\ N.s+P_{f2}\\\\P_{f2} = 0.22\ N.s[/tex]
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How long will it take a projectile to hit the ground if it is launched at 4.2 m/s off a 12.6 m high platform?
Answer: 3
Explanation:
I think you are supposed to divided in those problems? I'm not sure but if you aren't then please let me know. The equation I did was:
12.6 / 4.2 = 3
Hope this helps!! :)
A young diver is practicing his skills before an important team competition. Use the diagram below in order to analyze the energies of the diver and complete the statements below.
Where m = mass (kg), g = 9.8 m/s2, v = velocity (m/s), h = height (m), KE = kinetic energy (J), and GPE = gravitational potential energy (J).
Use the equations above to answer the following questions.
A diver with a mass of 90 kg is at a height of 10 m, and he has not jumped off of the board yet (v = 0 m/s). When the diver reaches a height of 5 m (Point C), his gravitational potential energy is
A. 1350 J
B. 8820 J
C. 4410 J
D. 0 J
and his velocity is
E. 4.5 m/s
F. 0 m/s
G. 3.2 m/s
H. 9.9 m/s
Please help will mark brainliest
[tex]\\ \sf\longmapsto GPE=mgh[/tex]
[tex]\\ \sf\longmapsto GPE=90(5)(9.8)[/tex]
[tex]\\ \sf\longmapsto G PE=4410J[/tex]
Now
It's converted to kinetic energy while reaching ground.
[tex]\\ \sf\longmapsto K.E=4410[/tex]
[tex]\\ \sf\longmapsto \dfrac{1}{2}mv^2=4410[/tex]
[tex]\\ \sf\longmapsto 90v^2=8820[/tex]
[tex]\\ \sf\longmapsto v^2=98[/tex]
[tex]\\ \sf\longmapsto v=9.9m/s[/tex]
Done
Answer:
Hope it will help you a lot.
Va A rail wagon of mass
5000 kg moving at a velocity
of 1.6 ms-1 collides with a
stationary wagon of mass
3000 kg (see Figure 4). After
the collision, the 3000 kg wagon
moves away at a velocity of
1.5 ms-1. Calculate the speed
and direction of the 5000 kg
wagon after the collision.
Answer:
0.7m/s
Explanation:
According to the conservation of linear momentum, the moment before a collision is equal to the moment after the collision. The equation is written as follows: [tex]m_{a}u_{a} + m_{b}u_{b} = m_{a}v_{a} + m_{b}v_{b}[/tex], where [tex]m[/tex] is the mass of the object, [tex]u[/tex] is the initial velocity, and [tex]v[/tex] is the final velocity.
Let's say the object [tex]a[/tex] is our moving wagon and the object [tex]b[/tex] is our stationary wagon. [tex]m_{a} = 500kg, u_{a} = 1.6ms^{-1}[/tex], [tex]m_{b} = 3000kg, u_{b} = 0[/tex], since the wagon is stationary, it doesn't have any initial velocity. After collision, the mass remains the same, but the velocity changes: [tex]v_{a} = ?, v_{b} = 1.5ms^{-1}[/tex]
We can observe that [tex]v_{a}[/tex] is what we're looking for according to the question. Now let's substitute our values.
[tex](5000 * 1.6) + (0) = 5000v_{a} + (3000 * 1.5)[/tex]
[tex]v_{a} = \frac{(5000 * 1.6) - (3000*1.5)}{5000}[/tex] = 0.7m/s
11. A tennis ball is thrown straight up in the air, leaving the person's hand with an initial velocity of 3.0 m/s, as shown to the right. What is the displacement of the ball above the person's hand?
Answer:
0.46m
Explanation:
If you have a train traveling 750 m in 63
seconds how fast is the train travelling?
Answer:
The train would be moving 47,250 mph
Miguel, a single teacher, earns $1,500 every two weeks (biweekly). He claims two allowances. What is his federal income tax withholding for each biweekly paycheck?
The federal income tax withholding for each biweekly paycheck for the single teacher is $259.9.
The given parameters:
Biweekly amount earned by the single teacher, = $1,500
The federal tax rate for single workers is given as;
amount between $436 and $1,506 = $34.9 plus 15%
The federal income tax withholding for each biweekly paycheck for the single teacher is calculated as follows;
income tax withholding = $34.9 + 0.15($1,500)
income tax withholding = $34.9 + $225
income tax withholding = $259.9
Thus, the federal income tax withholding for each biweekly paycheck for the single teacher is $259.9.
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If someone can help that would be cool
Answer:
1.5 cm
Explanation:
The ratio of areas is the square of the ratio of diameters, so cylinder A has (1/2)^2 = 1/4 the area of cylinder B.
The volume of the cylinder is jointly proportional to its area and its height. So, for a fixed volume, the height is inversely proportional to the area.
Cylinder B has 4 times the area of cylinder A, so any volume moved from cylinder A to B will require only 1/4 of the change in height that is required in cylinder A.
The red piston in cylinder B rises 1.5 cm.
Which of the following is the goal of physical fitness test? *
a. to determine the level of fitness.
b. to identify the area of development/improvement.
c. all of the above
d. to identify strengths and weaknesses.
Answer
C
hope this helps!!
*please mark brainliest if correct!! Trying to level up!!
a new planet is discovered that has twice the earth’s mass and twice the earth’s radius. on the surface of this new planet, a person who weighs 500 n on earth would experience a gravitational force of
Answer: 250n
Explanation:
The formula for gravitational force is: F = (gMm)/r^2
There are two factors at play here:
1) The mass of the planet 'M'
2) The radius 'r'
We can ignore the small M and the g, they are constants that do not alter the outcome of this question.
You can see that both M and r are double that of earth. So lets say earth has M=1 and r=1. Then, new planet would have M=2 and r=2. Let's sub these two sets into the equation:
Earth. F = M/r^2 = 1/1
New planet. F = M/r^2 = 2/4 = 1/2
So you can see that the force on the new planet is half of that felt on Earth.
The question tells us that the force on earth is 500n for this person, so then on the new planet it would be half! So, 250n!
What would be the impact on the environment if an artificial virus that attacked and destroyer chloroplast in plant cells was accidentally released by a research company?
Answer:Yes
Explanation:Because the virus is so dangerous
