A block slides to the right on a rough horizontal surface. The forces exerted on the block are shown above. Which of the following statements about the frictional force Ff exerted on the block is true?
A) It is the only force acting on the block that is caused by microscopic interactions.
B) It does not depend on the materials that the block and the surface are made of.
C) It is caused by gravitational interactions between the atoms in the block and the atoms in the surface.
D) It is the sum of all the microscopic contact forces between the bottom of the block and the surface.
Answers
Answer:
The correct option is;
A) It is the only force acting on the block that is causes by microscopic interactions
Explanation:
The force of friction is the force due to the relative motion of two surfaces in the presence of a perpendicular force acting between the surfaces.
The force of friction comes into play from the additional effect of the adhesion that is present between surfaces, the roughness of the surfaces, the contamination or deformation of the surfaces which is generated by the microscopic interactions be between the two surfaces, rather than the applied force.
The characteristics of the friction force, you can find which statements are correct:
D) It is the sum of all the microscopic contact forces between the bottom of the block and the surface.
The force is an image of the interactions between bodies, these interactions create binding energy that can be formed and broken, the friction force is the macroscopic sum of all these microscopic interactions between two different surfaces.
The magnitude of the friction force depends on the type of each surface, on rough surfaces the interaction area is high, therefore the friction force is high, on smooth surfaces the interaction area is small, therefore the force is small, a way to create superficiality is to place a layer of air between the two surfaces.
Based on these explanations, let's review the different statements:
A) False. The friction forces are caused by interaction, but between two bodies not within the same body, this is what maintains the shape and volume of the body.
B) False. The contact area depends on each surface and therefore each type of material
C) False. The gravitational force is this in the line of interaction between the two bodies, in this case the force is perpendicular to movement, not in the line of interaction.
D) True. It is the sum of the interactions in the contact between the two bodies, it agrees with the explanation above.
Using the characteristics of the friction force, we can find the statements that are correct is:
D) It is the sum of all the microscopic contact forces between the bottom of the block and the surface.
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Related Questions
how long would it take to get to the moon going around 75 miles an hour
Answers
someone pls help me will give brainlist
Answers
Answer:
The volume is 5.6 L
The mass is 100.2g
Explanation:
Quantitative observations are more based on numbers and values
A man runs at 7.5 m s-1 due east across the deck of a ship which moves at 10.0 m s-1 due north. Determine the resultant velocity of the man( his velocity relative to the water)
Answers
Answer:
12.5 m/s North/east
Explanation:
I thought of it as a graph. I basically just found the distance between the points (0,0) and (10, 7.5)!
The resultant velocity of the man is 12.5 m/s.
What is velocity?The rate at which a body's displacement changes in relation to time is known as its velocity. Velocity is a vector quantity with both magnitude and direction. SI unit of velocity is meter/second.
Velocity of the man: v₁ = 7.5 m/s (due east )
Velocity of the ship: v₂ = 10 m/s. ( due north.)
Hence, the man and the ship move in perpendicular direction.
So, his velocity relative to the water = the resultant velocity of the man
= √(7.5² + 10²) m/s = 12.5 m/s.
Hence, resultant velocity of the man is 12.5 m/s.
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A dog barks in a park and hears its echo after 0.5 seconds. The sound of its bark got reflected by a nearby building. The sound of speed in air is 346 m/s. The distance between the dog and the building is
Answers
Answer:
the answer is 173 m/s
Explanation:
the the sound traveled from the dog to the building and back to the dog in 0.5 seconds, every second passes the sound travels 346 m/s but if half a second passes then we divide 346 by 2 and get 173 m/s.
What's your favorite
family/cultural tradition? Why is this tradition your
favorite?
Answers
Answer:
Every summer we go and work at a summer camp. My whole family loves it, and it's something that always brings us closer.
Explanation:
Christmastime is without a doubt my favorite time of year, not because of Christmas itself, but because of the atmosphere leading up to it. I've always felt this way, and I believe that is because of my grandmother. My Nanny was the same way. She loved Christmas, and went all out every year. Her house was put in the local newspaper several times because of all the lights and decorations she put up. If only they could have gone inside the house!
Anyway, there are a lot of things I did with my grandma around Christmas, and if I had been asked my favorite tradition when I was a young child, I might have said “decorating,” or “making Christmas treats,” but looking back, it is what we would do every Christmas Eve.
Christmas Eve is last-minute shopping day for the adults of my family, and the only shopping day for the kids. I would head out with my dad in the morning and shop, then go to lunch with my grandpa, and then finally, I would go with my grandma. We would shop a little, and then she would always buy some fake poinsettias. We would then travel to a tiny cemetery that seemed like an hour away back then, and I would walk with her to her father's grave.
Even as a young child, I felt the emotions in the air when we visited his grave. She never cried or showed any signs of sadness, but I could just sense how special the moment was to her. When her mother passed away in 2013, we went to visit both of them, and the atmosphere only intensified.
My grandma died in March of 2015 after a long battle with cancer. Every Christmas Eve, I buy the most beautiful poinsettias I can find, and visit her grave. It's always freezing outside, being December, but I stand for a few minutes, remembering, and then I get back in my car and head home.
My fondest tradition isn't the most fun, or the most festive. It's the one that means the most to me. One day, I hope I can take my children or grandchildren with me, and I hope they'll feel everything that I felt.
Which of the following breakfasts is better than eating no breakfast at all?
A.
Sugary cold cereal and milk
B.
Fruit smoothie
C.
Doughnut
D.
All of the above
Answers
Answer:
D. all of the above
Explanation:
took the quiz
hope this helps :)
______ is a great example of a sport that creates a concentric contraction in
your muscles because the effort of lifting is short and powerful.
Dancing
Weightlifting
Horseback riding
Swimming
Answers
Answer:
weightlifting
Explanation:
100 points
And brainliest
A freeway exit curves with a radius of 30 m and a posted speed limit of 17.5 m/s. What is your radial
acceleration if you take this exit at the posted speed?
Answers
Answer:
10.21m/s²
Explanation:
Radial acceleration, also known as centripetal acceleration, refers to the acceleration of an object along the circular radius. It can be calculated using the formula:
a(r) = v²/r
Where a(r) = radial acceleration
v = velocity
r = radius of the circular path
According to the information provided in the question, velocity (v) = 17.5m/s, radius = 30m. Hence;
a(r) = v²/r
a(r) = 17.5²/30
a(r) = 10.208333
a(r) = 10.21m/s²
Aang and Appa are flying over Ba Sing Se. They covered 500 m in 30 seconds while heading east. What was their velocity?
Answers
Answer:
Explanation:
I need help to marysol;)
Help me plzzz I need answers
Answers
Answer:
i think it is B
Explanation:
The energy of electromagnetic waves increases with decreasing wavelength.
Which of the following statements support this claim?
O A. Dental patients need to wear lead aprons to protect themselves from X-rays but do not wear
protection from flashlights.
B. Both radio waves and gamma rays are invisible to human eyes.
C. Ultraviolet radiation causes sunburn but radio waves do not.
D. Microwaves are used for communication.
E. Gamma rays are used to kill cancer cells, but microwaves have no known effect on cancer
cells.
Answers
Answer: A C E
Explanation: i just did it and got it right lol
Answer:
its A, C, and E
Explanation:
i did it and got it right
A runner is jogging in a straight line at a
steady vr= 8.4 km/hr. When the runner is
L= 6.3 km from the finish line, a bird begins
flying straight from the runner to the finish
line at vb= 42 km/hr (5 times as fast as the
runner). When the bird reaches the finish
line, it turns around and flies directly back to
the runner.
Answers
Answer:
Total distance traveled by bird is 10.5 km.
Explanation:
Given that,
Velocity of runner= 8.4 km/hr
Distance = 6.3 km
Velocity of bird = 42 km/hr
Suppose, How far does the bird travel?
We need to calculate the time of bird
Using formula of time
[tex]t=\dfrac{d}{v_{b}}[/tex]
Put the value into the formula
[tex]t=\dfrac{6.3}{42}[/tex]
[tex]t=0.15\ hr[/tex]
We need to calculate the distance runner travels during time period
Using formula of distance
[tex]d=v_{r}\times t[/tex]
[tex]d=8.4\times0.15[/tex]
[tex]d=1.26\ km[/tex]
We need to calculate the distance of runner to FL
Using distance
[tex]d'=6.3-1.26[/tex]
[tex]d'=5.04\ km[/tex]
We need to calculate the net closing speed between runner and bird
Using speed
[tex]v'=v_{r}+v_{b}[/tex]
[tex]v'=8.4+42[/tex]
[tex]v'=50.4\ km/hr[/tex]
We need to calculate the time for runner and bird to meet
Using formula of time
[tex]t=\dfrac{d}{v'}[/tex]
Put the value into the formula
[tex]t=\dfrac{5.04}{50.4}[/tex]
[tex]t=0.1\ hr[/tex]
We need to calculate the distance covered by runner
Using formula of distance
[tex]d=vt[/tex]
Put the value into the formula
[tex]d=8.4\times0.1[/tex]
[tex]d=0.84\ km[/tex]
We need to calculate the distance covered by bird to runner
Using formula of distance
[tex]d=vt[/tex]
Put the value into the formula
[tex]d=42\times0.1[/tex]
[tex]d=4.2\ km[/tex]
We need to calculate the total distance
Using distance
[tex]D=6.3+4.2[/tex]
[tex]D=10.5\ km[/tex]
Hence, Total distance traveled by bird is 10.5 km.
a sled with no initial velocity accelerates at a rate of 3.2 m/s squared down a hill how long does it take to sled to go 15 m to the bottom
Answers
Answer:
After 3.06secondsExplanation:
Given that the following data are
acceleration a= 3,2m/s^2
distance s=15m,
time t=?
Applying the formula for the equation of motion we have
s=ut+1/2at^2
we no initial velocity (u=0)
substituting our given values into the expression we have
15=0*t+1/2(3.2)t^2
15=1/2(3.2)t^2
15=3.2t^2/2
30=3.2t^2
t^2=30/3.2
t^2=9.375
Squaring both sides we have
t=√9.375
t=3.06seconds
It will take the sled 3.06 seconds to get to the bottom
If you run the 100 m track at a velocity of 5.0 m/s, what is the time needed?
Answers
what are derive quantities
Answers
Answer:
Derived quantities are quantities that are calculated from two or more measurements. Derived quantities cannot be measured directly. They can only be computed. Many derived quantities are calculated in physical science. Three examples are area, volume, and density.
Answer:
What is derive quantities?
Derived quantities are those that may be expressed in terms of base or derived quantities by means of the mathematical symbols of multiplication and division only (no addition or subtraction or any other sign). ... The first group consists of derived quantities, which have proper units. Derived quantities are expressed as algebraic combinations of base quantities.
Examples of the Derive quantities
Derive Quantity and their units
Volume, V = m³Density, p = kgm⁻³Velocity, v = ms⁻¹Force, F = NAcceleration, a = ms⁻²
Enzymes have a certain temperature at which they work best. Temperatures above and
below this point will decrease enzyme activity. Which graph best illustrates the effect of
temperature on enzyme activity?
Answers
Answer:
B
Explanation:
It shows the increase in temperature and the decrease.
The best activity of enzyme is It increases and decreases.
What are Enzymes?A biological catalyst called an enzyme is usually always a protein. It accelerates a certain chemical reaction in the cell.
The enzyme is continuously employed during the reaction and is not destroyed. Each enzyme molecule found in a cell is unique and tailored to a particular chemical reaction.
A biological catalyst called an enzyme is often a protein, though it can also be RNA. A catalyst's purpose is to quicken the rate at which a reaction takes place.
Therefore, The best activity of enzyme is It increases and decreases.
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dont skip and pls help ASAP bc if you do i will give 10 pts + brainliest but pls hurry
Answers
ANSWER
Mass: The resistance of an object to acceleration, size-dependent
Volume: The amount of space an object occupies
Boiling point: The temperature at which a liquid boils and turns to vapor.
Melting point: The temperature at which a solid melts and turns to liquid
Density: Size-independent
Solubility: The ability of a substance (solvent) to dissolve when placed in a liquid (solute)
Magnetism: Size-dependent
EXPLANATION:
Mass: the more mass something has, the harder it is to accelerate. This is somewhat intuitive, but is also demonstrated in newton's third law. It's size-dependent because for an object of a given density, the size (volume) will change the mass.
Volume: big objects take up more space. If you put an apple in bucket filled to the brim with water, a little water will splash out, because the apple is now occupying the space that the water used to, but if you put in a watermelon, a lot of water will splash out, because the watermelon is taking up even more space.
Boiling point: when a liquid gets too hot, it will change to gas (example: water to steam)
Melting point: when a liquid gets too cold, it will change to a solid (example: water to ice)
Density: how much mass there is in a given volume. A sphere made of lead will have more mass than a sphere made of wood, even if they are the same size. Size-independent because a big lead sphere has the same density as a small lead sphere, they just have different masses.
Solubility: some substances dissolve in certain solvents, other's don't.
Magnetism: size-dependent because a bigger magnet is stronger than a smaller one if they are identical in every other way. More space means more domains means a stronger magnet.
Answer:
i agree
Explanation:
Explain one way in which friction actually helps people
Answers
Answer:
Friction creates warmth
What would happen if the electromagnet in an electric bell is replaced by an ordinary magnet
Answers
Answer:
The bell will not work as the Hammer will be attracted to the Gong and it will remain attracted because if there was an electromagnet the hammer will be released as soon as we stop pressing the switch but a Bar magnet is a permanent magnet and once it will get attracted to the Gong it will remain attracted.
Explanation:
Hope that helps!
it takes you 30 minutes to walk an average velocity of 2.om/s south to school. What is your displacement?
Answers
Answer:
3600 m SOUTH
Explanation:
avg velocity= (change displacement)/(change in time)
2.0 m/s= x/ (1800 s)
displacement= (2.0 m/s * 1800s)= 3600 m SOUTH
.......
sign explanation
2.0 m/s south= -2.0 m/s (downwards direction)
-2.0 m/s= x/ (1800 s)
x= -3600 m
A mass is dropped from a height h above the ground, and freely falls under the influence of gravity. Which graphs here correctly describes the displacement and velocity of the object during the time the object is falling? Consider the "up" direction to be positive.
Which graph is it?
Answers
Answer:
B
Explanation:
The only force acting on the block is gravity, so the block has a constant, negative acceleration. This means the velocity of the block is decreasing at a constant rate, so the answer is B, D, or E. Velocity is the rate of change of displacement, and answer choice B is the only one that has a displacement graph that matches that idea.
Answer: Graph B here correctly describes the displacement and velocity of the object during the time the object is falling. Option B is correct.
It is given that the mass of an object is dropped from height 'h' above the ground and "up" direction is taken to be positive.
It is required to find the graph which describes the displacement and velocity of the object during the time the object is falling.
Which graphs here correctly describes the displacement and velocity of the object during the time the object is falling?If any body falls freely towards the ground, then its acceleration is decreasing constantly with respect to time. That means velocity of an object will also be decreased as shown in graph B. Also we know that velocity is the rate of change of displacement.
As it is given in question that up direction is positive then it is also considered that downward be negative means decreasing.
Therefore, both the quantities are decreasing. So graph B correctly describes the displacement and velocity of the object during the time the object is falling.
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What is an astronomical unit?
the average distance between planets in the solar system
the average distance between the Earth and the moon
the approximate diameter of the Sun including its atmosphere
the average distance between the Earth and the Sun
Answers
Answer:
D
Explanation:
HURRRY PLEASEEEEE!!!
In photosynthesis, what two compounds are produced during the light-dependent reaction then used in the light-independent reaction?
A) ATP and NADPH
B) ATP and ADP
C) NADP+ and ADP
D) NADPH and NADP+
Answers
Answer:
The answer choice is: A) ATP and NADPH
Explanation:
Your question is asking the components that are created during light - dependent reaction, and then used in independent reaction. That would be shown in the photo below!
ATP and NADPH is created from light dependent then transfered and transformed into different components from the calvin cycle (light independent cycle)
Two compounds are produced during the light-dependent reaction then used in the light-independent reaction - A) ATP and NADPH
Photosynthesis is a process that takes place in the Chloroplast of plant cells. Autotrophs obtain their energy source (food) in the presence of sunlight.
The photosynthesis process occurs in two distinct stages; light-dependent reaction and light-independent reactions.
the light reactions take place in the thylakoid membranes of chloroplasts.The light-dependent reactions use light energy to make two molecules needed for the next stage of photosynthesisThese molecules are the energy storage molecule ATP and the reduced electron carrier NADPH.Thus, two compounds are produced during the light-dependent reaction then used in the light-independent reaction - A) ATP and NADPH
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What is the total energy equation?
Total energy = kinetic energy / potential energy
Total energy = kinetic energy * potential energy
Total energy = kinetic energy + potential energy
Total energy = kinetic energy - potential energy
Answers
Answer:kinetic
Explanation:
An object is said to move from a position of 10m East to a position of 5m west. Determine the object's distance travelled.
Answers
Answer:
5 i think
Explanation:
True or False: A reference point is stationary
Answers
Answer:
True
Explanation:
A Reference point is stationary
Can an object experiencing constant acceleration change its direction of motion? Explain.
Answers
Answer:
Yes it can.
Explanation:
A object undergoing a constant acceleration has a constantly changing velocity. If the acceleration always points in the same direction as the velocity, the trajectory will be no different than if there were no acceleration, but in general acceleration will change the trajectory.
An athlete kicks a soccer ball with a velocity of 24.2 m/s at a 26 degree angle from the ground.
Find the horizontal component of the starting velocity. (Vx)
Answer: I got was 23.71 or if you round it it'd be 23.72 but it still says that I'm wrong
Answers
Answer:
The horizontal component is 18 cos(35) = 14.745 m/s
The vertical component is 18 sin(35) = 10.324 m/s
Explanation:
What did scientists create using scientific measurements?
Answers
Answer:
lines?
Explanation:
A baseball is thrown to a height of 10 m and then falls back and is caught. What is the displacement of the baseball for the entire time period described?
a) -10m
b) 0m
c) 10m
d) 20m
Answers
That’s because the ball ends back at the starting point.