As the box is moving with a constant velocity, the two forces acting on the box are canceling each other.
Then friction force = 80 Newtons but in the opposite direction.
Friction force = Mu * Normal force exerted by ground = Mu * weight of box
So we find Mu.
Mu = coefficient of friction between box and horizontal surface
= Force of friction / weight = 80 / 50 * 9.81 = 0.163
When an identical box is placed on top, the force of friction is
= Mu * total weight = 0.163 * (50+50) * 9.81 = 159.9 Newtons
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.
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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How much force is necessary to stretch a spring 0.5 m when the spring constant is 190 N/m?
Answer:
95 N
Explanation:
The International Space Station (ISS) orbits Earth at an altitude of 4.08 × 105 m above the surface of the planet. At what velocity must the ISS be moving in order to stay in its orbit?(1 point)
A) 7.91 × 10^3 m/s
B) 3.12 × 10^4 m/s
C) 7.66 × 10^3 m/s
D) 8.17 × 10^3 m/s
Satellite A is orbiting Earth at an altitude of 500 km and Satellite B is orbiting 800 km above the surface. How does the velocity of Satellite A compare to the velocity of Satellite B?(1 point)
A) It depends on the masses of the satellites.
B) The velocity of Satellite A is greater than the velocity of Satellite B.
C) The velocity of Satellite B is equal to the velocity of Satellite A.
D) The velocity of Satellite A is less than the velocity of Satellite B.
What is the direction of the net force acting on a satellite as it orbits Earth at a constant speed?(1 point)
A) in the direction the satellite is moving
B) toward the center of Earth
C) away from the center of Earth
D) opposite the direction the satellite is moving
What happens to the gravitational force and orbital velocity of a satellite as the satellite transfers to an orbit that is closer to Earth?(1 point)
A) The gravitational force decreases and the velocity increases.
B) The gravitational force increases and the velocity increases.
C) The gravitational force decreases and the velocity decreases.
D) The gravitational force increases and the velocity decreases.
Newton's second law and universal gravitation law allow to find the results for questions about the motion of satellites in orbit are:
1) The correct answer is D: v = 8.17 10³ m/s
2) The correct answer is B
The velocity of Satellite A is greater than the velocity of Satellite B.
3) The correct answer is B
Toward the center of Earth
4) The correct answer is B
The gravitational force increases and the velocity increases.
Newton's second law establishes a relationship between force, mass, and the acceleration of bodies.
F = m a
In the case of the satellite the force is given by the law of universal gravitation.
[tex]F = - G \frac{Mm}{r^2 }[/tex]
Where G is the constant of universal gravitation. M and m the mass of each object and r the distance between them.
In this case the satellite is in a circular orbit, therefore the acceleration is centripetal.
[tex]a = \frac{v^2}{r}[/tex]
We substitute.
[tex]G \frac{Mm}{r^2} = m \frac{v^2}{r}[/tex]
[tex]\frac{GM}{r} = v^2[/tex]
Let's analyze the answers to find the correct one.
1) They indicate the height of the space station r = 4.08 10⁵ m and ask the speed.
[tex]v= \sqrt{ \frac{6.67 \ 10 ^{-11} 5.9 \ 10^{24}}{4.08 \ 10^6 } }[/tex]
v = 9.82 10³ m / s
The correct answer is D.
2) Satellite A has an orbit of hₐ = 500 km and satellite b an orbit of
h_b = 800 km
The distance from the center of the earth to each satellite is:
rₐ = R + hₐ
r_b = R + h_b
rₐ = 6.37 106 + 500 10³ = 6.87 10⁶ m
r_b = 6.37 10⁶ + 800 10³ = 7.17 10⁶ m
Let's find the ratio of the speeds
[tex]\frac{v_a}{v_b} = \sqrt{ \frac{r_b}{r_a} } \\\frac{v_a}{v_b} = \sqrt{ \frac{7.17}{6.87} }[/tex]
[tex]\frac{v_a}{v_b}[/tex] = 1,022
we see that the speed of satellite a is slightly greater than the speed of satellite b.
Let's analyze the claims.
A) False. The speed does not depend on the mass of the satellites.
B) True. The velocity of a is slightly greater than the velocity of b.
C) False. The speed of a is greater.
D) False. The speed of a is greater.
3) As the orbit is circular, the force must be radial, that is, it points towards the center of the earth.
Let's analyze the claims.
A) False. The speed modulus does not change, therefore there is no acceleration in the direction of the satellite.
B) True. Aim for the center of the Earth, change the direction of the velocity.
C) False. Aim for the scepter of the earth.
D) false. The modulus of velocity is constant and the direction changes towards the center of the earth, therefore the force must go towards the center of the earth.
4) The force in the law of universal gravitation increased as the distance decreased.
When a satellite approaches the earth its speed must increase since the speed is proportional in inverse of the square root of the distance.
Let's examine the claims.
A) False. The attraction force increases.
B) True. You agree with the explanation.
C) False. The gravitational force increases.
D) False. Speed increases.
In conclusion, using Newton's second law and the universal law of gravitation we can find the results for the questions about the movement of satellites in orbit are:
1) The correct answer is D: v = 8.17 10³ m/s
2) The correct answer is B
The velocity of Satellite A is greater than the velocity of Satellite B.
3) The correct answer is B
Toward the center of Earth
4) The correct answer is B
The gravitational force increases and the velocity increases.
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Answer:
1. 7.66 × 10^3 m/s
2. The velocity of Satellite A is greater than the velocity of Satellite B.
3. toward the center of Earth
4. The gravitational force increases and the velocity increases.
Explanation:
PLEASE HELP WILL GIVE BRAINLIEST
Answer:
D, A
Explanation:
#1
Height is same for all cars
So they all will arrive at same speed but A will come first
Option D
How did Thomson's model get its name?
Answer:
thats actually a really good question. sadly i don't know the answer to it. but im sure that there are others who can!
7. If the speed of light in medium-1 and medium-2 are 2.5x 10 m/s and 2x 10 m/s respectively then the refractive index of medium-1 with respect to medium-2 is (a) 3/2.5 (b) 2/2.5 (c) 2.5/3
Answer:
Answer to the question is 4 / 5
To know the answer with proof see the above attachmentexplain how the spray painting process makes use of static electricity
Answer:
The spray paint gun is charged positively, which causes every paint particle to become positively charged. Since the paint particles all have the same charge, they repel each other and produce a fine mist of paint which is sprayed towards the wall/car.
Answer:
xerography can i get brainliest
Explanation:
Mechanical energy is similar to thermal energy because they both?
Answer:
Mechanical energy is the ordered movement of the molecules as a single unit. Thermal energy is the random movement of the molecules. Mechanical energy can be 100% converted to thermal energy, but thermal energy cannot be fully converted to mechanical energy.
Over a period of 2.50 seconds, a speedboat accelerates uniformly from 18.5 m/s to 46.5 m/s. What is the acceleration of the speedboat relative to the shore?
According to the question, the acceleration of the speedboat relative to the shore is found to be 11.2 [tex]m/sec^2.[/tex]
What is Acceleration?Acceleration may be characterized as the rate of change of the velocity of an object with respect to time. It is a vector quantity, as it defined both magnitude and direction. This allows you to measure how fast velocity changes in meters per second squared (m/s^2).
According to the question,
The initial velocity of the boat = 18.5 m/s.
The final velocity of the boat = 46.5 m/s.
Difference in velocity = Final velocity - Initial velocity = 46.5-18.5 = 28 m/s.
The formula for calculating the acceleration of the boat is as follows:
a = Difference in velocity/time taken.= 28/2.50 = 11.2 [tex]m/sec^2[/tex].
Therefore, the acceleration of the speedboat relative to the shore is found to be 11.2 [tex]m/sec^2.[/tex]
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Calculate the elastic potential energy stored in a spring if it has a force constant of 150 N/m. the spring is extended to a length of 0.30m
Answer:
6.75J
Explanation:
U=1/2KΔx²
U=0.5* 150*0.30^2
What important role does each play in an exercise regiment?
Answer: There are five principles of fitness out of which two are overload principle and rest and recovery principle. Overload principle is one of the most important principle which tell that to gain and improve the fitness one should do the hard work.
Slowly and gradually the intensity and time of exercise are increased so that our body can adapt to the hard work. Overload principle plays an important role in improving the skills and improving performance during exercise and sports.
Rest and recovery principle is important to relax the body and release the stress that happens due to intense training like in case of weight lifting one day rest should be taken to repair and rebuild the muscles. This allows the body to encounter the fatigue and improve performance.
Explanation:
name an instrument that is used to measure atmospheric pressure
Answer:
Barometer also called barometric pressure.
Answer:
A barometer
Explanation:
There are two types of barometers;
Mercury barometerAneroid barometer[tex]{}[/tex]
What is the smallest value of the force F such that the 8.0 kg block will not slide down the wall? The coefficient of static friction between the block and the wall is 0.4.
Select one:
a. 10N
b. 100N
c. 200N
d. 98N
The smallest value of the force that will make the block not to slide down is 10 N.
We'll begin by calculating the normal reaction. This can be obtained as follow:
Mass (m) = 8 KgAcceleration due to gravity (g) = 10 m/s²Normal reaction (N) =?N = mg
N = 8 × 10
N = 80 N
Finally, we shall determine the frictional force.
Coefficient of friction (μ) = 0.4Normal reaction (N) = 80 NFrictional Force (F) =?F = μN
F = 0.4 × 80
F = 32 N
Since the frictional force is 32 N, therefore, a force lesser than the frictional force will make the block not to slide down.
From the options given above, only option A has a force that is lesser than the frictional force.
Therefore, the correct answer to the question is Option A. 10 N
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What is the current in a 120V circuit if the resistance is 20Ω?
We have: [tex]I=\frac{U}{R}=\frac{120}{20}=6A[/tex]
ok done. Thank to me :>
Answer:
The Current is 6 Ampere.
Step-by-step explanation:
Given :
[tex]\small\red\bull[/tex] Voltage = 120V[tex]\small\red\bull[/tex] Resistance = 20ΩTo Find :
[tex]\small\red\bull[/tex] CurrentUsing Formula :
[tex] \star{\small{\underline{\boxed{\sf{ I = \dfrac{V}{R}}}}}}[/tex]
[tex]\small\blue\star[/tex] I = Current[tex]\small\blue\star[/tex] V = Voltage[tex]\small\blue\star[/tex] R = ResistanceSolution :
Substituting all the given values in the formula to find Current :
[tex]{\dashrightarrow{\pmb{\sf{ I = \dfrac{V}{R}}}}}[/tex]
[tex]{\dashrightarrow{\sf{ Current = \dfrac{Voltage}{Resistance}}}}[/tex]
[tex]{\dashrightarrow{\sf{ Current = \dfrac{120}{20}}}}[/tex]
[tex]{\dashrightarrow{\sf{ Current = \cancel{\dfrac{120}{20}}}}}[/tex]
[tex]{\dashrightarrow{\sf{ Current = 6A}}}[/tex]
[tex]{\star{\underline{\boxed{\sf{\red{ Current = 6A}}}}}}[/tex]
Hence, the Current is 6 Ampere.
[tex]\rule{300}{1.5}[/tex]
an object moves 15.0 m north and then 11.0 m south. find both the distance it has traveled and the magnitude of its displacement.
White light is an _____ mixture of all the colors.
Answer:
White light is a combination of all colors in the color spectrum.
Explanation:
It has all the colors of the rainbow. Combining primary colors of light like red, blue, and green creates secondary colors: yellow, cyan, and magenta
1. What do machines do? Change the amount of force one exerts. Decrease the amount of work that is done. Increase the amount of work that is done. Eliminate friction.
Answer: increase the amount of work that is done?
Explanation:
I’m not entirely sure to be honest but I’ll just use my logic here. Machines are made to increase efficiency and production. Machines are made to save time and energy as a pose to human work. So several machines can mass produce a lot of things and keep business booming. I’m not very good at explaining things but I hope this makes sense eventually.
Which of these best describes the relationship between the incident ray, the reflected ray, and the normal for a curved mirror?(1 point)
The angle that the incident ray makes with the normal is different than the angle that the reflected ray makes with the normal. All points on a curved mirror have the same normal.
The angle that the incident ray makes with the normal is different than the angle that the reflected ray makes with the normal. All points on a curved mirror have the same normal.
The angle that the incident ray makes with the normal is the same as the angle that the reflected ray makes with the normal. Different points on a curved mirror have a different normal.
The angle that the incident ray makes with the normal is the same as the angle that the reflected ray makes with the normal. Different points on a curved mirror have a different normal.
The angle that the incident ray makes with the normal is different than the angle that the reflected ray makes with the normal. Different points on a curved mirror have a different normal.
The angle that the incident ray makes with the normal is different than the angle that the reflected ray makes with the normal. Different points on a curved mirror have a different normal.
The angle that the incident ray makes with the normal is the same as the angle that the reflected ray makes with the normal. All points on a curved mirror have the same normal.
For a curved mirror, all points have the same normal and the angle of incidence is also equal to the angle of reflection.
According to the laws of reflection, the incident ray, reflected ray and normal all lie on the same plane. For a curved mirror, the normal remains the same at all points along the curved mirror.
Again, the angle made between the incident ray and the normal is the same as the angle made between the reflected ray and the normal. Therefore, the angle of reflection is equal to the angle of incidence.
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NEED HELP ASAP 40 POINTS L!!!! Jaden is interested in learning more about the basics of astrono ny and looking more closely at the sky all by himself. He wantS to get a basic starter telescope to help him with this endeavor, and his teacher SuggestS an organization that might be able to help him with this. What organization is Jaden's teacher likely referring to? The Little Astronomers Celestial Sightseeing Group The Beginning Astronomy Organization Astronomers Without BordersS
How far does an object travel if it is moving at a speed of 4 m/s for 3.2 seconds?
Answer:
12.8 meters
Explanation:
m/s means meters per second. So, to find how far it would travel in 3.2 seconds, you would multiply 4 meters every second by 3.2 seconds.
4×3.2=12.8 meters
A 10.0-kg crate slides along a raised horizontal frictionless surface at a constant speed of 4.0 m/s. The crate then slides down a frictionless incline and across a second, roughened horizontal surface as shown in the figure. What is the kinetic energy of the crate as it reaches the lower surface?
The kinetic energy of the crate as it reaches the lower surface is 80 J
Kinetic energy is the energy possed by an object in motion. Mathematically, the kinetic energy can be expressed as follow:
KE = ½mv²
With the above formula, the kinetic energy of the crate can be obtained as follow:
Mass (m) = 10 KgVelocity (v) = 4 m/sKinetic energy (KE) =?KE = ½mv²
KE = ½ × 10 × 4²
KE = 5 × 16
KE = 80 J
Therefore, the kinetic energy of the crate is 80 J
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What is the frequency of a wave with a wavelength of 15 m and a wavespeed of
300 m/s?
Answer: f=20 (i think)
Explanation:
all I did was divide 300 and 15.
300/15= 20
Helpppppppp pleaseeeee!!
The mass of an atom is concentrated in its
a. nucleus
b. electron
c. neutron
d. angstrom
e. isotope
Other than temperature, which property also has an effect on the rates of chemical reactions?
A.Color of reactants
B.Concentration of reactants
C.Solubility of reactants
D.Volume of reactants
Other than temperature, the property that also has an effect on the rates of chemical reactions is the concentration of the reactants. The correct answer is B
The rate of chemical reaction means how chemical react with respect to time or as a function of time. The rate of chemical reaction tells us the speed or how fast chemicals react.
There are many factors that can affect the rate of chemical reaction. Temperature is one of them. Increase in temperature will increase the rate at which chemical react.
The color of reactants, solubility of reactants and volume of reactants have nothing to do with the rate of chemical reaction.
Other than temperature, the property that also has an effect on the rates of chemical reactions is the concentration of the reactants.
Other factors affecting the rate of chemical reaction are:
the physical state of the reactants surface area temperature and the presence of a catalystTherefore, the correct answer is option B
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This is not meant to be a long, mathematically-intensive problem. If you find yourself going down that road, you might want to rethink your approach.
Answer:
rethink your approach to what?
Explanation:
7. A drag car takes off at the green light heading in a straight line. The car goes
from a complete stop to 45m/s in 9 seconds. What is its acceleration?
Answer:
405
Explanation:
If the car stops at 45m/s in 9 seconds then it took the car 405 meters to stop
How many volts would it take to push 1 amp through a resistance of 1 ohm?
Answer:
[tex]1\; \rm V[/tex].
Explanation:
Ohm's Law give the following relationship between the potential [tex]V[/tex] across a conductor, the electrical resistance [tex]R[/tex] of that conductor, and the current [tex]I[/tex] through that conductor:
[tex]V = I \, R[/tex].
It is given that the current through this conductor is [tex]I = 1\; {\rm A}[/tex], and that the electrical resistance of this conductor is [tex]R = 1\; \rm \Omega[/tex].
Note, that the unit of electrical resistance Ohm is a composite unit; [tex]1\; {\rm \Omega} = 1\; {\rm V \cdot A^{-1}}[/tex] (volts per ampere.)
Substitute the value of [tex]I[/tex] and [tex]R[/tex] into the equation [tex]V = I \, R[/tex] from Ohm's Law to find the potential across this conductor:
[tex]\begin{aligned}V &= I \, R \\ &= 1\; {\rm A} \times 1\; {\rm \Omega} \\ &= 1\; {\rm A} \times 1\; {\rm V \cdot A^{-1}} \\ &= 1\; {\rm V}\end{aligned}[/tex].
The planets never travel in a straight line as they orbit the Sun. According to Newton's second law of motion, this must mean that _________. the planets are always accelerating a force is acting on the planets the planets have angular momentum the planets will eventually fall into the Sun
Explanation:
The planets never travel in a straight line as they orbit the Sun. According to Newton's second law of motion, this must mean that: Your Answer: The planets have angular momentum.'
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According to Newton's second law of motion, this must mean that force is acting on the planets. The correct option is (b).
As per Newton's second law of motion, an object's acceleration is inversely related to its mass and directly proportional to the net force exerted on it.
The curving courses of the planets in their solar system show that they are constantly changing their direction, as it causes them to accelerate.
The planets are being accelerated in the direction of the Sun as a result of the Sun's gravitational pull on them. The planets continually speed up toward the Sun due to the centripetal force required to maintain them in their orbits, which is caused by the gravitational attraction between the Sun and the planets. As a result, the planets orbit the Sun in elliptical patterns rather than in a straight line.
Hence, According to Newton's second law of motion, this must mean that force is acting on the planets. The correct option is (b).
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The complete question is:
The planets never travel in a straight line as they orbit the Sun. According to Newton's second law of motion, this must mean that _________.
(a) the planets are always accelerating
(b) a force is acting on the planets
(c) the planets have angular momentum
(d) the planets will eventually fall into the Sun
what class of motion did aristotle attribute to the moon?
What is the mass of a box if it accelerated 5 m/s from a force of 12 N?
Answer:
60
Explanation:
You multiply the acceleration and the force and you get your answer