Answer:
The magnitude of the friction force that the floor exerts on the box is 8.5 newtons.
Explanation:
From Newton's Laws of Motion and given that box is moving at constant velocity, the net acceleration of the box is zero, meaning that magnitude of friction force is equal to the magnitude of the horizontal applied force. Please notice that friction force is the reaction to the horizontal force. The equation of equilibrium for the box is:
[tex]\Sigma F = F - f = 0[/tex] (1)
Where:
[tex]F[/tex] - Horizontal applied force, measured in newtons.
[tex]f[/tex] - Friction force, measured in newtons.
If we know that [tex]F = 8.5\,N[/tex], then the magnitud of the friction force that the floor exerts on the box is:
[tex]f = F[/tex]
[tex]f = 8.5\,N[/tex]
The magnitude of the friction force that the floor exerts on the box is 8.5 newtons.
A sample of an unknown metal has a mass of 0.5 kg. Adding 1985 J of heat to the metal raises its temperature by 10 K. What is the specific heat of the metal
Answer:
Cp = 397 [J/kg*K]
Explanation:
By means of the energy equation for heat transfer in substances and objects, we can calculate the specific heat. In this way, we have the following equation.
[tex]Q=m*C_{p}*DT[/tex]
where:
Dt = temperature change = 10 [K]
m = mass = 0.5 [kg]
Q = heat = 1985 [J]
Cp = specific heat [J/kg*K]
Now replacing:
[tex]1985=0.5*C_{p}*10\\C_{p}=\frac{1985}{0.5*10}\\C_{p}=397[\frac{J}{kg*K} ][/tex]
The center of mass of a cow and the center of mass of a tractor are 208 meters apart. The magnitude of the gravitational force of attraction between these two objects is calculated to be 1.8 × 10-9 newtons.
What would the magnitude of the gravitational force of attraction be between these two objects if they were 416 meters apart?
A.
1.62 × 10-9 newtons
B.
3.6 × 10-10 newtons
C.
9 × 10-10 newtons
D.
4.5 × 10-10 newtons
Answer:
Choice: D.
Explanation:
Newton’s Law of Universal Gravitation
It states that objects attract each other with a force that is proportional to their masses and inversely proportional to the square of the distance between them. The formula is:
[tex]\displaystyle F=G{\frac {m_{1}m_{2}}{r^{2}}}[/tex]
Where:
m1 = mass of object 1
m2 = mass of object 2
r = distance between the objects' center of masses
G = gravitational constant: [tex]6.67\cdot 10^{-11}~Nw*m^2/Kg^2[/tex]
The center of mass of a cow is at a distance of r=208 m from the center of the mass of a tractor. The gravitational force of attraction is [tex]F=1.8\cdot 10^{-9}\ N[/tex]. It's required to find the new force of attraction F' if the distance was r'=416 m.
It can be noted that r'=2r. If the distance is doubled, the new force is:
[tex]\displaystyle F'=G{\frac {m_{1}m_{2}}{(2r)^{2}}}[/tex]
[tex]\displaystyle F'=\frac{1}{4}G{\frac {m_{1}m_{2}}{r^{2}}}[/tex]
Substituting the original value of F:
[tex]\displaystyle F'=\frac{1}{4}\cdot 1.8\cdot 10^{-9}\ N[/tex]
Operating:
[tex]\displaystyle F'=4.5\cdot 10^{-10}\ N[/tex]
Choice: D.
A researcher asks the same group of kids to define "happiness" when
they were 5 years old, 10 years old, and again at 20 years old. They then
analyzed how the kids' idea of "happiness" changed over the years. This is
an example of which type of study?
case study
cross-sectional study
longitudinal study
naturalistic observation
double blind study
Answer:
naturalistic observation
Explanation:
explain the basic concept that involves projectiles
describe how an electromagnet can be switched on and off.
Answer:The magnetic field around an electromagnet is just the same as the one around a bar magnet. It can, however, be reversed by turning the battery around. Unlike bar magnets, which are permanent magnets, the magnetism of electromagnets can be turned on and off just by closing or opening the switch.
TRUE OR FALSE: Aquaponics decreases cost for equipment, energy usage, and land usage. *
Answer: b
Explanation:
b
Answer:
b
Explanation:
b
A car is coasting backwards downhill at a speed of 3.0 m/s when
the driver gets the engine started. After 2.5 sec, the car is
moving
uphill at 4.5 m/s. Assuming that uphill is the positive
direction, what is the car's average acceleration?
If a car is coasting backward downhill at a speed of 3. 0 meters / s when the driver gets the engine started. After 2.5 sec, the car is moving uphill at 4.5 meters / second . Assuming that uphill is the positive direction the average acceleration of the car would be 3.0 meters / second².
What is acceleration?The rate of change of the velocity with respect to time is known as the acceleration of the object. Generally, the unit of acceleration is considered as meter / seconds².
As given in the problem If a car is coasting backward downhill at a speed of 3. 0 meters / s when the driver gets the engine started. After 2.5 sec, the car is moving uphill at 4.5 meters / second .
The average acceleration of the car = + 4.5 - ( - 3 .0) / 2.5
= 3.0 meters / second ²
Thus , the average acceleration of the car would be 3.0 meters / second².
To learn more about acceleration here, refer to the link given below ;
brainly.com/question/2303856
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A person wants to redesign a large room in a house to have less echoing of sound and more sunlight. Which design solution will best match the persons needs?
(A.) Hang curtains over the windows that will transmit sound waves and absorb light waves.
(B.) add pillows to the furniture that will reflect sound waves and refract light waves.
(C.) Place a thick white carpet on the floor that will absorb sound waves and reflect light waves.
(D.) Add a large mirror on the wall that will refract sound waves and reflect light waves.
Answer:
(A.) Hang curtains over the windows that will transmit sound waves and absorb light waves
Compared to the cells in a healthy body, Elisa’s cells are getting far fewer ____________________ molecules.
Answer:
glucose
Explanation:
What is polarization. How can we remove it?
Which statement best describes how scientists and engineers work together
in the research and development cycle?
O A. Engineers make a new discovery about nature, and then scientists
do experiments to verify it.
O B. Scientists develop new technology, and then engineers use it to
solve design problems.
C. Scientists make a discovery, and then engineers use it to help
them solve problems with their designs.
D. Engineers develop a new technology, and then scientists use it to
solve design problems.
Answer:
C
Explanation:
1 point
(e) When food is eaten, some of the radiation the food emits is detectable
outside the body. Which type of radiation would not be detectable outside
the body? Tick one box.*
alpha
beta
gamma
Answer:
alpha radiation
Explanation:
e ) Alpha particles can not be detected outside body as it can not penetrate the layer of skin of our body .
So correct answer is "alpha radiation" .
What happens to an object's gravitational potential energy as it falls from some height?
Answer:
Decreases
Explanation:
As an object falls from some height, the gravitational potential energy of the object decreases.
Potential energy is the energy due to the position of a body.
The potential energy is mathematically expressed as:
Potential energy = mass x acceleration due to gravity x height
So, potential energy is directly proportional to mass and height.
The higher the mass and height, the more the potential energy.
4 properties of light
Which describes a condition of the neritic zone?
few organisms
ample sunlight
changing salinity
frigid temperatures
Answer:
ample sunlight
Explanation:
Neritic zone have ample of sunlight
What is Neritic zone ?The neritic zone is covered with generally well - oxygenated water , receives plenty of sunlight , have relatively stable temperature , has low water pressure and stable salinity levels .
Hence , correct option is option b) ample sunlight
Learn more about Neritic zone :
https://brainly.com/question/17067679?referrer=searchResults
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The energy of a given wave in the electromagnetic spectrum is 2.64 × 10-21 joules, and the value of Planck's constant is 6.6 × 10-34 joule·seconds. What is the value of the frequency of the wave?
Answer:
the answer is b
wjejehebe ehshw es
27. Improvements in space technology have greatly helped scientists better understand the stars, planets, and other
celestial bodies in our universe. How do technological advances in astronomy benefit our society on Earth?
A. Technological advancements in astronomy allow scientists to better understand Earth and find solutions to
preventing global warming
B. Technological advancements in astronomy have led to the development of thousands of products such as
new materials, medical devices, and communications satellites.
C. Technological advancements in astronomy have led to the development of many theories of how the
universe began and how the Earth formed.
D. Technological advancements in astronomy have helped improve our society's economy.
Answer:
B
Explanation:
Technological advancements in astronomy have led to the development of thousands of products such as
new materials, medical devices, and communications satellites.
For example, the production of instruments like telescopes, microscopes, and other measuring devices now enables us to identify things that we couldn't examine with the naked eye.
Similarly, the development of communication satellites has led to the emergence and improvements in the mobile network industry.
PLEASE HELP ASAP I'LL GIVE BRAINLY!!
Answer: b or c
Explanation: on khan academy
can anyone help me with this last question?
Answer:
v = 39.6 m/s (first answer option)
Explanation:
Use conservation of mechanical energy.
The starting is completely potential energy and the final is all kinetic energy:
[tex]m*g*h=\frac{1}{2}*m*v^2\\g * h=\frac{1}{2} v^2\\9.8*80=\frac{1}{2} v^2\\v^2=1568\\v\approx 39.6\,\,m/s[/tex]
which agrees with the first answer shown.
Why do you think it is important to have a system to arrange items in the grocery store? What will happen if we don’t have a system?
ILL MARK BRAINLEST
Question 13: A food web of the Yellowstone National Park ecosystem is
provided below. If a sudden outbreak of disease severely reduced the
number of wolves in Yellowstone National Park very rapidly, what are two
changes that might happen to the local food web? Fully explain using
claim, evidence, and reasoning.
Answer:
they all will die and so will we
Explanation:
Answer:
3 animals will thrive better
Explanation:
If the number of wolves is reduced, 3 animal species usually eaten by the wolves will have a better chance of survival.
Explain the principles of work in physics.
A force, 10 N drags a mass 10 kg on a horizontal table with an acceleration of 0.2
m/s2. If the acceleration due to gravity is 10 m/s2, the coefficient of friction between
the moving mass and the table is?
Answer:
20&£+)##&843&()-_££-()&_2+0&&-£_!)
Explain how neutrons enable a nuclear chain reaction to take place. (2)
Answer:
Explanation:
In addition to the 'daughter' products, two or three neutrons also explode out of the fission reaction and these can then collide with other uranium nuclei which are unstable so these cause further fission reactions. This is known as a chain reaction .
Hope this helps
estion 20
Not yet answered Market out of 100 Flag question
Slim Jim lifts a 8 kg box to a height of 2 m. How much work did he do to the box?
Which list orders the types of forces from weakest at the top to strongest at
the bottom?
O A. Hydrogen bonds
Van der Waals forces
Metallic bonds
lonic bonds
B. Metallic bonds
Hydrogen bonds
Van der Waals forces
Ionic bonds
O C. Van der Waals forces
Hydrogen bonds
Metallic bonds
lonic bonds
D. Ionic bonds
Metallic bonds
Hydrogen bonds
Van der Waals forces
The list of the type of forces that are weakest at the top to strongest at the bottom is
Ionic bonds Metallic bondsHydrogen bondsVan der Waals forcesWhat are the types of forces?The type of force that impacts the objects are physical, tension and normal, gravitational, electric, and magnetic force. The force that is strongest is that of the iconic bonds and the weakest is that of the Van der Waals force.
Find out more information bout the types of forces.
brainly.com/question/26197441
Answer:
C. Van der Waals forces
Hydrogen bonds
Metallic bonds
Ionic bonds
Explanation:
This list orders the types of forces from weakest at the top to strongest at the bottom. Van der Waals forces are relatively weak intermolecular forces, followed by hydrogen bonds which are stronger. Metallic bonds are even stronger, and ionic bonds are the strongest among the listed forces.
A flashlight is shone on a mirror. As you move the flashlight to increase the angle of incidence of the light on the mirror, the angle of the reflection also changes. How does the angle of reflection change?
Answer:
the angle of reflection also increases
Explanation:
this is because the law of reflection states that the angle of incidence equals to the angle of reflection, thus, if the angle of incidence increases, angle of reflection should also increase, basically , think as if the angle of incidence is the same thing as the angle of reflection
hope this helps, if not please report it someone else can try it
the length of iron rod at 100 C is 300.36 cm and at 159 C is 300.54 cm.Calculate its length at 0 c and coefficient of linear expansion of iron
Answer:
The length at 0 °C is 300.05 cm
Coefficient of linear expansion of iron is 1.02×10¯⁵ C¯¹
Explanation:
From the question given above, the following data were obtained:
Length (L₁) at 100 °C = 300.36 cm
Temperature 1 (θ₁) = 100 °C
Length (L₂) at 159 °C = 300.54 cm
Temperature 2 (θ₂) = 159 °C
Length (L₀) at 0 °C =?
Coefficient of linear expansion (α) =?
L₁ = L₀ (1 + θ₁α)
300.36 = L₀ (1 + 100α) ....(1)
L₂ = L₀ (1 + θ₂α)
300.54 = L₀ (1 + 159α) ..... (2)
Divide equation (2) by (1)
300.54 / 300.36 = L₀ (1 + 159α) / L₀ (1 + 100α)
1.0006 = (1 + 159α) / (1 + 100α)
Cross multiply
1.0006 (1 + 100α) = (1 + 159α)
1.0006 + 100.06α = 1 + 159α
Collect like terms
1.0006 – 1 = 159α – 100.06α
0.0006 = 58.94α
Divide both side by 58.94
α = 0.0006 / 58.94
α = 1.02×10¯⁵ C¯¹
Substitute the value of α into anything of the equation to obtain L₀. Here we shall use equation (2).
300.54 = L₀ (1 + 159α)
α = 1.02×10¯⁵ C¯¹
300.54 = L₀ (1 + 159 ×1.02×10¯⁵)
300.54 = L₀ (1 + 0.0016218)
300.54 = L₀ (1.0016218)
Divide both side by 1.0016
L₀ = 300.54 / 1.0016
L₀ = 300.05 cm
Summary:
The length at 0 °C is 300.05 cm
Coefficient of linear expansion of iron is 1.02×10¯⁵ C¯¹
How does the initial velocity of a projectile affect its range?
N - Projectiles with larger initial velocity will go farther
0 - Projectiles with larger initial velocities will not go as far
P-Initial velocity has no effect
Plzzz yaar guys help I really need this ( crying emoji )
Answer:
I believe it is the first one
A 20 Kg box is sliding across a horizontal table at 10m/s. If the coefficient of Friction is 0.5, what is the acceleration of the box?
By Newton's second law,
• the net vertical force on the box is
∑ F = n - mg = 0
where n = magnitude of the normal force, m = mass of the box, and g = acceleration due to gravity; then
n = mg = (20 kg) (9.8 m/s²) = 196 N
• the net horizontal force on the box is
∑ F = -f = -ma
where f = mag. of kinetic friction and a = acceleration of the box. Since
f = µn
where m is the coefficient of kinetic friction, so that
f = 0.5 (196 N) = 98 N
Then the box's acceleration is
-98 N = - (20 kg) a → a = (98 N)/(20 kg) = 4.9 m/s²