If the coefficient of static friction is 0.3, then the minimum force required to get it moving is equal in magnitude to the maximum static friction that can hold the body in place.
By Newton's second law,
• the net vertical force is 0, since the body doesn't move up or down, and in particular
∑ F = n - mg = n - 50 N = 0 ==> n = 50 N
where n is the magnitude of the normal force; and
• the net horizontal force is also 0, since static friction keeps the body from moving, with
∑ F = F' - f = F' - µn = F' - 0.3 (50 N) = 0 ==> F' = 15 N
where F' is the magnitude of the applied force, f is the magnitude of static friction, and µ is the friction coefficient.
Potential Energy (kJ)
Reaction Progress →
A) Does this graph represent an endothermic or exothermic reaction? Explain your answer. (2 points) HELP PLEASE ITS URGENT !!
Answer:
Endothermic reaction
Explanation:
(a) Endothermic reaction: These are reactions that absorb heat from the surrounding during a chemical reaction. The enthalpy change for endothermic reaction is always positive, and the energy level of the product is higher than that of the reactant
(b) Exothermic reaction: These are reactions that release heat to the surrounding during chemical reaction. The enthalpy change for exothermic reaction is always positive, and the energy level of the product is lower than that of the reactant.
From the diagram in the question,
Since the energy level of the product is higher than that of the reactant then the reaction is an endothermic reaction and as such, ΔH is positive
the electric charge remains at rest in a. static electricity, b. current electricity, c. none of these
Answer:
Option (a) is correct.
Explanation:
The electric charge is the inherent property of matter which appears due to the deficiency of charge or the excess number of electrons.
There are two types of charges, positive and negative.
When an object has deficiency of charge it becomes positive charge and when it gains some electrons, it becomes negative charge.
When the charge is in motion, it is called electric current and when the charge is at rest, it is called static current.
A charge at rest contributes the electric field only while the charge is in motion contributes the electric and magnetic field both.
Atoms can create fields to interact with each other without touching.
True
or
False
Answer:
True
Explanation:
True, atoms create electromagnetic fields that form repulsion to keep them from touching.
The core of transformer is laminated.......
a.to reduce the loss of energy in the form of heat across the transformer
b.to reduce the voltage of AC
c.to decrease the voltage of AC
d. to change the maginetic flux
Answer:
A. to reduce the loss of energy in the form of heat across the transformer
Explanation:
The core of the transformer is laminated to minimise the energy as they interfere with the efficient transfer of energy from the primary coil to the secondary one. The eddy currents cause energy to be lost from the transformer as they heat up the core - meaning that electrical energy is being wasted as heat.
A vehicle starts from rest with a uniform acceleration of 2m/s2.Find the final velocity of the vehicle after covering a distance of 400m
Answer:
40
Explanation:
vi=0
a=2
vf=?
d=400
vf^2=vi^2+2ad
vf^2=0+2×2×400=1600
vf=√1600=40m/s
A water wave passes by a floating leaf that is made to oscillate up and down two complete cycles each second, which means that the wave's frequency is
Answer:
2 Hz.
Explanation:
Frequency is simply defined as the number of appearances of a periodic event occurring per time. It is usually measured in cycles/second.
Now, in this question, we are told that there are 2 cycles for each second.
Thus, we can say that the frequency is 2 cycles/1 s = 2 Hz.
Why does time have a direction? Please give your ideas I want to see them. Brainliest f0r most effort.:)
Answer:
it's a rule like water !!!!
Explanation:
Most importantly, time appears to run forward always never backwards. in other words there's perceived arrow of time and there's thermodynamic arrow of time, and they always point in a forward direction
for every system there are more states that seem chaotic then states that seem ordered.
the arrow of time seems to have something to do with that tendency. but to get from one instance to another where things get more entropy, we already need some kind of time, gotta admit that.
some (physicists) believe that time is an illusion, that the whole universe is already set in stone, like a block (the idea is therefore called block universe). from the perspective of a godlike outside observer the universe would be like a book, or a 4D movie. the characters might feel a movement of things in a direction, but rewinding it wouldn't feel different in any instance because the order in wich things happen is already written.
a different idea is that there are infinite many different futures and the further they are away, the less we can know for sure about them in a physical way. and this might also be work for the past, so that different parts could lead to one present.
when macroscopic information is deleted, it might not be reversible, so the past gets ultimately blurry. one example for deletion of macroscopic information this is the Library of Alexandria wich burned down.
all the quantum information is still conserved, but the order of things (like letters on pages) is lost and could have been in different configurations before. we can't ultimately not even see the past, as much as we would try.
personally the idea that the past is written in stone but the future is in flux doesn't make any sense for me. because than I could have free will now, but not from the perspective 10 days later.
the present would be a very special thing than, the stage where the universe likes to play.
maybe we can get a grasp on time if we look at it like rules for a game, like a cardboard game.
To get from one configuration to the next ,we must follow rules. like throwing dice and moving in monopoly.
gravity would be a simple real world example for such a rule, a natural law.
But no one would have a firm clue where this rules came from.
TLDR: I don't know and neither does anyone else for sure, not even top notch scientists.
the hardest questions are easy to formulate, but maybe even impossible for us to answer in a satisfying way. I hope we will understand those hard questions better one day, and maybe even get answers.
A boy travels 12km east wards to a point B and then 5km southwards to another point C. Calculate the difference between the magnitude of the displacement of the boy and the distance travelled by him
The difference b/w the displacement and total distance traveled is 4km.
Explanation.
▪ total distance - displacement
= 17 km - 13 km
= 4 km...answer
What type of material does not transfer heat well?
Which would be used to measure the distance between the earth and a planet ,meter ruler or a measuring tape? Why?
Answer:
parallax
Due to foreshortening, nearby objects show a larger parallax than farther objects when observed from different positions, so parallax can be used to determine distances. To measure large distances, such as the distance of a planet or a star from Earth, astronomers use the principle of parallax.
Which of the following statements are true with respect to the law of conservation of mass?
i) Mass is conserved during a chemical reaction.
ii) Amount of products formed can be determined using law of conservation of mass.
iii) Mass is destroyed during a chemical reaction.
O i only true
Both i and in
All three statements are true
All three statements are false
Answer:
Only (I) is true
i) Mass is conserved during a chemical reaction.
The weight of a body is 600 N. What is the mass of the body on the surface of the earth?
Explanation:
soln,
weight=600N
mass=?
gravity=9.8 m/s²
now,
mass=weight/gravitymass=600/9.8mass=61.22kghope it helps.
stay safe healthy and happy.Answer:
m = 61.22 kg
Explanation:
F = 600 N
g = 9.8 m/s²
m = ?
F = mg
600 = m(9.8)
---> m = 61.22 kg
A body of mass 8000 moving with a velocity of 2.5m/s collides with a stationery twice the mass of the first body. After impact the mass moves to 1.0m/s Find the speed of the first body.
Answer:
the final speed of the first ball is 0.5 m/s
Explanation:
Given;
mass of the first body, m₁ = 8000 kg
mass of the second body, m₂ = 16,000 kg
initial velocity of the first body, u₁ = 2.5 m/s
initial velocity of the second body, u₂ = 0
final velocity of the stationary mass, v₂ = 1 m/s
let the final velocity of the first body = v₁
Apply the principle of conservation of linear momentum;
m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂
8000(2.5) + (16,000 x 0) = 8000v₁ + 16,000 (1)
20,000 + 0 = 8000v₁ + 16,000
8000v₁ = 4000
v₁ = 4000/8000
v₁ = 0.5 m/s
Therefore, the final speed of the first ball is 0.5 m/s
Define ELASTIC LIMIT, YIELD POINT AND ULTIMATE TENSILE STRENGTH?
[tex] \green{\huge{\red{\boxed{\green{\mathfrak{QUESTION}}}}}} [/tex]
ELASTIC LIMIT, YIELD POINT AND ULTIMATE TENSILE STRENGTH.
[tex] \orange{\underline{\huge{\bold{\textit{\green{\bf{TOPIC}}}}}}} [/tex]
Mechanical Properties Of Solid.
[tex] \huge\green{\boxed{\huge\mathbb{\red A \pink{N}\purple{S} \blue{W} \orange{ER}}}}[/tex]
[tex] \bold{ \green{PART \: \: (1):-}} \\ \bold \green {{ ELASTIC \: \: LIMIT}}[/tex]
It is also called yield point
In this limit, energy provided to the material to cause deformation when removed then the material returns to its own shape and size.
In this limit each body shows elastic nature
[tex] \bold{ \red{PART \: \: (2):-}} \\ \bold \red {{YIELD \: \: STRENGTH}}[/tex]
It is the fix amount of the energy which causes fixed permanent set of deformation.
In this body shows plastic deformation.
The level of stress that corresponds to the yield point is referred to as the yield strength of the material.
[tex]\bold{ \purple{PART \: \: (3):- \:ULTIMATE }} \\ \bold \purple {{TENSILE \: \: STRENGTH}}[/tex]
It is the amount of the stress which causes permanent set of deformation after the yield point.
Body show perfect plastic deformation.
This shows a permanent set of deformation.
[tex] \red \star{Thanks \: And \: Brainlist} \blue\star \\ \green\star If \: U \: Liked \: My \: Answer \purple \star[/tex]
¿Cuántos electrones por segundo pasan a través de una sección de alambre que lleva una corriente de 0.70 A.?
Answer:
The number of electrons flowing per second is [tex]4.375\times 10^{18}[/tex].
Explanation:
How many electrons per second pass through a section of wire that carries a current of 0.70 A.?
Current, I = 0.7 A
time, t = 1 s
According to the definition of current, let the charge is q.
q = I t
q = 0.7 x 1 = 0.7 C
Let the number of electrons is n.
[tex]n =\frac{q}{e}\\\\n = \frac{0.7}{1.6\times 10^{-19}}\\\\n = 4.375\times 10^{18}[/tex]
suppose the pilot starting again from rest opens the throttle part.way at constant acceleration the airboat then covers a distance of 60.0m in 10.0s find the net force action on the boat
Answer:
Acceleration is 1.2 m/s^2.
Explanation:
initial velocity, u = 0
distance, d = 60 m
time, t = 10 s
Let the acceleration is a.
use second equation of motion
[tex]s= u t +0.5 at^2\\\\60 = 0 + 0.5 \times a \times 10\times 10\\\\a = 1.2 m/s^2[/tex]
Now according to the Newton's second law
Force = mass x acceleration
Let the mass is m.
F = m x 1.2 = 1.2 m Newton
Examine the equation.
-2(-x + 9) = 2(x - 9)
2x - 18 = 2x - 18
This equatior has
Answer:
same value because both sides are equal
Explanation:
equal value
In both the camera and the __________, light enters a narrow opening and is projected onto a photosensitive surface. Group of answer choices
Answer: The HUMAN EYE
Explanation:
The human eye is made up of different parts which ranges from controlling the amount of light that enters the eye to the focusing of the image that is formed. The camera is a device which is both mechanically and electronically operated which shares a number of similarities with the eye.
In the human eye, the IRIS helps to regulate the amount of rays passing through the pupil to the lens by either contracting or dilating in light or dark environment respectively. While in the camera, the DIAPHRAGM controls the amount of light entering the camera.
The PUPIL serves as the passage for light into the eye while in the camera, the APERTURE does the same.
The photosensitive surface in the eye is the YELLOW SPOT while in the camera, the photosensitive surface is the PHOTOGRAPHIC FILM.
Un proton penetra perpendiculares en un campo magnetico de 5 teslas con una velocidad de 2.10 m/s calcula
Answer:
The magnetic force acting on the proton is 1.68 x 10^-18 N.
Explanation:
magnetic field, B = 5 T
speed , v = 2.1 m/s
charge q = 1.6 x 10^-19 C
Angle, A = 90 degree
The magnetic force on the charge particle is given by
[tex]F = q v B sin A\\\\F = 1.6\times 10^{-19}\times 2.1\times 5\times sin 90\\\\F = 1.68\times 10^{-18} N[/tex]
Help me and I'll make u Brainliest and follow u
26. D. crushing the sugar cube and dissolving it in water.
27. A. atom
28. B. molecule
29. B. plum pudding model of Joseph John Thomson
30. B. He used cathode ray tubes which showed that all atoms contain tiny negatively charged subatomic particles or electrons
31. D. protons and neutrons are relatively heavier than electrons.
As the motor speeds up, the value of current decreases because of A. Friction loss B. Increase in resistance C. Increase in back emf D. All mentioned above
Answer:
C. Increase in back emf
Explanation:
As the current through the field winding decreases the field strength also decreases and the back-emf is reduced, as a result the motor speeds up.
When the motor begins to speed-up, an additional back EMF is generated due to induction which reduces armature current. This also results in reduced strength of the field flux. The back emf generated is not enough to reduce the armature current which could stop the acceleration of the motor and the motor further accelerates.
what is acceleration
[tex]\boxed{\large{\bold{\blue{ANSWER~:) }}}}[/tex]
[tex]\sf What \: is \: acceleration? \\ \\ \sf The \: rate \: of \: change \: of \: velocity \: of \: an \\ \sf object \: with \: respect \: to \: time \\ \sf is \: known \: as \: acceleration. [/tex]
Fluorometers are designed so that the path of the excitation light is at a right angle to the path of the emitted light. What is the purpose of this design
Answer: prevent excitation light from reaching the detector
Explanation:
A fluorometer refers to the device that's used in the measurement of parameters that are of visible spectrum fluorescence. They also prevent excitation light from reaching the detector.
These parameters are used in the identification of the amount and presence of molecules in a medium.
Which of the following statements describes how tectonic plates move?
A. They move from the crust to the core.
B. They move from the mantle to the inner core.
C. They move from the inner core to the outer core.
D. They move slowly on top of the mantle.
Answer:
D
Explanation:
The tectonic plates move on the mantle, sort of floating on it as they are part of the crust. When they collide things like mountain ranges form, and big earthquakes happen.
A glass tube in the shape of a letter J has the shorter limb sealed and the longer limb open. Mercury is poured into the tube until the levels in either limb is the same when the tube is vertical.In this position, the length of the air column in the sealed limb is 6.3cm.More mercury is then poured into the tube until the length of the trapped air column is 42cm.Calculate the difference in the levels of mercury in the limbs if a nearby mercury barometer reads 75.0cm and the reading of a nearby thermometer has not changed?
Answer:
35.4 cm
Explanation:
We have that when the level of mercury on either limb is the same, the pressure of the trapped air, P₁ = Atmospheric pressure
Also the initial height of the mercury in the tube = The reading of the barometer = 75.0 cm
The initial length of the air column, l₁ = 6.3 cm
The final length of the air column, l₂ = 4.2 cm (The length is expected to decrease due to compression)
The volume, V = l × A
Where;
A = The cross sectional area of the tube
Therefore, the volume of the air column is directly proportional to the length of the air column
∴ V ∝ l
According to Boyles law, we have;
P₁·V₁ = P₂·V₂
Where;
P₁ = The initial pressure in the air column before more mercury is added
V₁ = The initial volume occupied by the air in the air column
P₂, and V₂ are the final pressure and volume of the air column respectively
Given that V = l·A, we can write;
P₁·l₁·A = P₂·l₂·A
P₂ = P₁·l₁·A/(l₂·A) = P₁·l₁/(l₂) = P₁ × 6.3/4.2 = 1.5·P₁
The pressure in the air column after more mercury is added, P₂ = 1.5 × P₁
P₁ = Atmospheric pressure, therefore;
The pressure in the air column after more mercury is added, P₂ = 1.5 × Atmospheric pressure
Pressure = h·ρ·g
Where;
ρ = The density of the substance
g = The acceleration due to gravity
h = The height of the column of the fluid
Given that the density and the gravitational force, can be taken as constant, we have that the pressure of the fluid is directly proportional to the height of the fluid column
Therefore, when the pressure doubles, the height of the fluid column doubles, and when the factor of increase is 1.5, we have;
The final level of the mercury, h₂ = 1.5·h₁ = 1.5×75 cm = 112.5 cm
The initial length of the closed end of the J tube, [tex]h_{closed1}[/tex] = 6.3 cm + 75 cm = 81.3 cm
The final length of the mercury in the closed end, [tex]h_{closed2}[/tex] = 81.3 cm - 4.2 cm = 77.1 cm
The difference in the level of mercury, Δh = h₂ - [tex]h_{closed2}[/tex]
∴ Δh = 112.5 cm - 77.1 cm = 35.4 cm
The difference in the levels of mercury in the limbs, Δh = 35.4 cm
Physicist Max Planck showed how objects like stars give off different colors based on their temperature. What color are the hottest stars
Answer:
the brightest found are Blue - White with
Explanation:
The energy emission of objects increases with their temperature, specifically Wien described the process in an expression
[tex]\lambda_{maximum}[/tex] T = 2,898 10⁻³
With this expression we can find the temperature of the stars by the color they emit.
Specifically the Sun has a color of 550 nm which corresponds to 5400K
bright stars have a BLUE color corresponding to 7500K
the brightest found are Blue - White with a temperature of 20000K
Question 9 of 10 The data table shows how the amplitude of a mechanical wave varies with the energy it carries. Analyze the data to identify the mathematical relationship between amplitude and energy. Use your equation to find the energy if the amplitude is 8 units. Amplitude Energy 1 unit 2 units 2 units 8 units 3 units 18 units 4 units 32 units
Answer:
A Em
1 ½ K
2 ½ k 4 = 2k
3 ½ k 9 = 4.5 k
4 ½ k 16 = 8k
Explanation:
The total mechanical energy of a simple harmonic movement is constant in time, let's look for the energy at one end of the movement, where the velocity of the body is zero.
Em = U = ½ k x²
at the end x = A
Em = ½ k A²
Let's build a table for the energy and as a function of the amplitudes of the movement
A Em
1 ½ K
2 ½ k 4 = 2k
3 ½ k 9 = 4.5 k
4 ½ k 16 = 8k
as a function of the lowest energy
1 Eo = ½ k
2 4Eo
3 9 Eo
4 16Eo
Stellar nucleosynthesis a. produces elements with an atomic number greater than 26 (iron). b. is a process that happens during the death of stars. c. is the process by which stars create the heavier elements. d. is a stream of atoms emitted from a star.
Answer:
C: the process by which stars create the heavier elements
Explanation:
Stellar nucleosynthesis is defined as the process of nuclear fusion by which heavier elements are formed within stars by from the combination of protons and neutrons gotten from the nuclei of lighter elements.
Looking at the options, the correct one is Option C
What factors could the skater change to apply the same amount of torque but increase the rate of his spin
Answer:
The moment of inertia should be decreased.
Explanation:
The torque is given by
Torque = Moment of inertia x angular velocity
To keep the torque constant, the spin rate be increased when the moment of inertia decreases.
The moment of inertia of the body are the efforts to put the object in rotation.
A 5,400 W motor is used to do work. If the motor is used for 640 s, about how much work could it do?
8.4 J
4,800 J
6,000 J
3,500,000 J
Answer:
3,500,000 J
Explanation:
WORK = POWER * TIME
WORK= 5400 * 640
=6456000 J = 3,500,000 J
Answer:
D
Explanation:
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