Answer:
Because alkali metals are so reactive, they are found in nature only in combination with other elements. They often combine with group 17 elements, which are very “eager” to gain an electron.
Explanation:
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Calculate the speed of an object that travels 75m in 15s
Answer:
speed =distance/time taken
5 m/s
The 180-mm disk is at rest when it is placed in contact with a belt moving at a constant speed. Neglecting the weight of the link AB and knowing that the coefficient of kinetic friction between the disk and the belt is 0.54, determine the angular acceleration of the disk while slipping occurs.
Answer:
[tex]\mathbf{\alpha = 25.88 \ rad/s^2 }[/tex]
Explanation:
Consider the force due to friction:
[tex]F = \mu_kN -------- (1)[/tex]
where;
N = normal reaction
[tex]\mu_k[/tex] = coefficient of kinetic friction.
Via the horizontal direction, the forces of equilibrium are:
[tex]\sum F_x = \sum(F_x) _{eff} \\ \\ N- F_{AB} \ cos \theta = 0 \\ \\ F_{AB} \ cos \theta = N ------ (2)[/tex]
where;
[tex]\theta[/tex] = angle of AB is associated with the horizontal;
[tex]F_{AB}[/tex] = force exerted by AB
Let's take a look at the equilibrium of forces along the vertical direction.
[tex]\sum F_y = \sum (F_y)_{eff} \\ \\ F+F_{AB} sin \theta - W = 0\\ \\ \mu_k N + F_{AB} sin \theta -mg =0 \\ \\ F_{AB} sin \theta = mg - \mu_kN-------(3)[/tex]
By dividing (3) by (2), we get:
[tex]\dfrac{F_{AB} sin \theta }{F_{AB} cos \theta} = \dfrac{mg - \mu_k N}{N} \\ \\ tan \theta = \dfrac{mg-\mu_kN}{N} \\ \\ Ntan \theta = mg - \mu_kN \\ \\ N(tan \theta + \mu_k ) = mg \\ \\ N = \dfrac{mg}{tan \theta + \mu_k}[/tex]
By replacing the obtained value of N into:
[tex]F = \mu_k N[/tex]
we have:
[tex]F = \mu_k (\dfrac{mg}{tan \theta + \mu_k}) \\ \\ \\ F = \dfrac{mg \mu_k}{tan \theta + \mu_k}[/tex]
Moment about center A can be expressed as:
[tex]\sum M_A = \sum (M_A) _{eff} \\ \\ Fr = I \alpha\\ \\ \alpha = \dfrac{Fr}{I}[/tex]
where;
[tex]\alpha[/tex] = angular acceleration of the disc
I = mass moment of inertia
r = radius of disc
By replacing F and I; ∝ becomes:
[tex]\alpha = \dfrac{\bigg( \dfrac{mg \mu_k}{tan \theta + \mu_k} \bigg) r}{\dfrac{1}{2}mr^2}[/tex]
[tex]\alpha = \dfrac{2g}{r} \dfrac{\mu_k}{tan \ \theta + \mu_k}------- (4)[/tex]
where;
g = 9.8 m/s²
r = 0.18 m
[tex]\mu_k = 0.54[/tex]
θ = 60°
[tex]\alpha = \dfrac{2(9.8)}{0.18} (\dfrac{0.54}{tan \ 60+ 0.54})[/tex]
[tex]\mathbf{\alpha = 25.88 \ rad/s^2 }[/tex]
Ms. Senko is moving a desk around her classroom, the desk weighs 125N.
The Coefficient of Static Friction between the desk legs and the floor is
0.35. The Coefficient of Kinetic Friction between the desk legs and the
floor is 0.23 WHAT IS THE FORCE OF FRICTION ON THE table as it is moving
Answer:
Static force of friction = 428.75 N
Kinetic Force of Friction = 281.75 N
Explanation:
The static force of friction is equal to Coefficient of static Friction * Mass * g
= 0.35 *125 * 9.8
= 428.75 N
The Kinetic force of friction is equal to Coefficient of kinetic Friction * Mass * g
= 0.23 *125 * 9.8
= 281.75 N
A piano tuner detects 3 beats per second when she is tuning a string to a tuning fork of frequency 440 Hz. When she tightens the string, which increases the frequency of the string, the frequency of the beats initially goes down, and as she keeps increasing the frequency of the string, the frequency of the beats starts to increase. What was the original frequency of the string
Answer:
[tex]F_o=437Hz[/tex]
Explanation:
From the question we are told that:
Frequency of Turning fork [tex]F_t=440Hz[/tex]
Number of beats detected [tex]n=3[/tex]
Generally the equation for Original frequency [tex]F_o[/tex] of the string is mathematically given by
[tex]F_o=F_t-F_b[/tex]
Where
[tex]F_b[/tex] Beat frequency
[tex]F_b=1Hz*n\\F_b=1Hz*3[/tex]
Therefore
[tex]F_o=440-3[/tex]
[tex]F_o=437Hz[/tex]
A boy held a ball in the air what force is he applying?
Answer:
strength
Explanation:
Answer:
Potential energy
Explanation:
Since the boy is holding is, it is not moving. So, it has potential energy. Also, since it is in the air, it has gravitational potential energy.
Which of the following would not create an inclusion fossil?
A. Insufficient oxygen-(when an organism becomes trapped in amber)
B. Low temperatures-(when an organism becomes frozen in a glacier)
C. Extremely high temperatures-(when an organism is burned in fire)
A ladder 5.0 m long leans against a wall inside a spaceship. From the point of view of a person on the ship, the base of the ladder is 3.0 m from the wall, and the top of the ladder is 4.0 m above the floor. The spaceship moves past the Earth with a speed of 0.90c in a direction parallel to the floor of the ship. Find the angle the ladder makes with the floor as seen by an observer on Earth
Answer:
the angle the ladder makes with the floor as seen by an observer on Earth is 71.9°
Explanation:
Given the data in the question and as illustrated in the diagram below.
speed of the ship v = 0.90c
base of the ladder from the wall x₀ = 3.0 m
top of the later above the floor y = 4.0 m
we determine angle θ.
from the diagram,
tanθ = y/x₀
tanθ = y / x₀√( 1 - v²/c² )
we substitute
tanθ = 4.0 / 3.0√( 1 - ((0.9c)²/c²) )
tanθ = 4.0 / 3.0√( 1 - ((0.9²)c²/c²) )
tanθ = 4.0 / 3.0√( 1 - (0.9²) )
tanθ = 4.0 / 3.0√( 1 - 0.81 )
tanθ = 4.0 / 3.0√0.19
tanθ = 4.0 / 1.30766968
tanθ = 3.058876
θ = tan⁻¹( 3.058876 )
θ = 71.8965 ≈ 71.9°
Therefore, the angle the ladder makes with the floor as seen by an observer on Earth is 71.9°
what is molecular force and gravitational force with their examples .
Answer:
Gravitational force is the force of attraction on a body by earth. Example - Leaves and fruits fall from a tree downwards towards the ground due to the gravitational pull. ... T-shirt for is basically the force Of attraction On a body And this force of attraction on the body is by Earth.
Intermolecular forces act between molecules. ... Intermolecular forces are weaker than intramolecular forces. Examples of intermolecular forces include the London dispersion force, dipole-dipole interaction, ion-dipole interaction, and van der Waals forces.
Explanation:
Explanation:
I am sure you are Clear. Thanks.
In which region is there most likely to be a volcano?
A, African plate
B, north american plate
C, south America plate,
D, Pacific plate
Answer:
D. Pacific plate
Explanation:
took the quiz
Diana has just been diagnosed with "pre-diabetes," and her doctor has instructed her to watch her intake of sugar. This is easy at home, but this weekend she will be going to a restaurant with her family. What should she do? (1 point) Order anything on the menu labeled "sugar-free" or "fat-free." Use a phone app to check the sugar content in items or ingredients on the menu. Order something off the salad options and skip the soda or dessert. Split an entrée with a friend to reduce her calorie intake at the meal.
Answer:
sugar free
Explanation:
she should most likely take anything sugar free and avoid any bread, bread can increase your blood level as well, my mother had pre diabetes and what she did was eat salads and drink vegetable smoothies until your sugar goes down. splitting an entrée won't do anything, you technically get the same amount of sugar so at the point just eat the whole meal.
A racing car on a straight accelerates from 100mph to 316 mph in three seconds what is the acceleration?
Answer:
72mph/sec
Explanation:
The car goes from 100mph to 316mph in three seconds. Meaning it increases its speed by (316 - 100)mph in three seconds. That is 216 mph increase in three seconds. So, we divide the speed increase by the amount of time the increase occurred over. We get:
216mph / 3sec = 72mph/sec, our final answer
Hope it made sense. I would appreciate Brainliest, but no worries.
The Mississippi River is continually forming and changing the land mass in the southern part of Louisiana. This kind of build up of land is called a
Answer:
dfdfsdf s
Explanation:
fsdfsd fsd fds f vsdvads
A baby was born on his due date, but doctors determined that a valve in his heart was too short to adequately pump blood to his body. The baby passed away after eight months. Which best describes the cause of his death?
He had a congenital condition.
He was premature.
He died in an accident.
He suffered SIDS.
Answer:
He had a cogenital condition
Explanation:
cogenital conditions are present before or at the time of birth and are considered birth defects
Answer:
The answer is C- He had a congential condition.
Explanation:
Edge
Which two elements make up most of the Sun’s mass?
Question 4 options:
Hydrogen and oxygen
Carbon and nitrogen
Oxygen and carbon
Hydrogen and helium
Answer:
hydrogen and helium
Explanation:
i got it 100 percent. Hope this Helps!
A bicycle pump contains 200 cm3 of air and is connected to a bicycle tyre. The volume of the tyre is 800 cm3. The pressure of the air in the tyre (it is ‘flat’) is 1.0 atmosphere, the same as the air in the pump. (= volume1). What is the total volume of the air initially?
Answer:
The total initial volume of air in the tire is 800 cm³
Explanation:
Given;
volume of air in the bicycle pump, V₁ = 200 cm³
volume of the tire, V₂ = 800 cm³
The total initial volume of air in the tire is 800 cm³ and when the pump is pushed in, the total volume of air in the tire becomes 200 cm³. This occurs because the new air pumped into the tire through the bicycle pump compresses the air that was previously in the tire and raises the pressure of the tire that was initially flat.
From Boyle's law, a decrease in volume causes an increase in pressure.
What is the female counterpart of sperm?
the vagina
the ovum
the zygote
the epididymus
Answer:
The zygote
Explanation:
The sperm is what fertilized the egg and the zygote is basically part of the female egg cell.
Hope this Helps!Hope this Helps!:)Answer:
the answer is the ovum on edge
Explanation:
A woman has one damaged fallopian tube. The damage completely blocks the opening of the tube at the ovary. How will this most likely affect her fertility?
Her likelihood of conceiving will be reduced by at least 50%.
Her eggs, if fertilized, will not implant properly.
Her eggs will not mature inside the ovary.
Her chances of conceiving twins will be doubled.
Answer:Her likelihood of conceiving will be reduced by at least 50%.
Explanation:
EDGE 2020
Answer:
Her likelihood of conceiving will be reduced by at least 50%
Explanation:
took the test on edge, got it right
My MASS on Earth (g = 9.81 m/s^2) is 90kg. What is my MASS on the moon
(g = 1.62 m/s^2)? *
what is a black hole what does it do
Answer:
What's a black hole?=> Black holes are points in space that are so dense they create deep gravity sinks. Beyond a certain region, not even light can escape the powerful tug of a black hole's gravity.
What does it do?=> Anything that ventures too close—be it star, planet, or spacecraft—will be stretched and compressed like putty in a theoretical process aptly known as spaghettification.
[tex] \infty \infty [/tex]
Which of these is an example of tertiary prevention?
A. Getting screened for skin cancer
B. Avoiding smoking and drinking alcohol
C. Dialysis for damaged kidneys
D. Washing hands
Explanation:
because a tertiary prevention is when the person is already infected with the disease
1.A body of mass 10kg falling freely was found to be falling at a rat of 20m/s what force will stop the body in 2second?
Answer:
50N
Explanation:
force it is falling with can be found by mass into acceleration and then devide by half to find force that could stop it in 2 sec
Very large forces are produced in joints when a person jumps from some height to the ground. (a) Calculate the magnitude of the force (in N) produced if a 62.0 kg person jumps from a 0.800 m-high ledge and lands stiffly, compressing joint material 1.50 cm as a result. (Be certain to include the weight of the person.) N (b) In practice the knees bend almost involuntarily to help extend the distance over which you stop. Calculate the magnitude of the force (in N) produced if the stopping distance is 0.300 m. N (c) Compare both forces with the weight of the person.
Answer:
a) F = 3.3 10⁴ N, b) F = 2.2 10³ N, c) force when rigid is 15 times greater than when bending the knees
Explanation:
For this exercise we can use the relationship between work and the variation of kinetic energy
K₀ = ½ m v²
the final kinetic energy is zero because the person is stationary
W = (∑ F) x
W = W x - F w
the weight is in the same direction of the displacement therefore the work is positive and the force applied, by the floor, is in the opposite direction to the displacement, consequently the work is negative
we substitute
( W- F ) x = 0-K₀
F = W + K₀ /x
F = mg + [tex]\frac{1}{2} \frac{mv^2 }{2x}[/tex]
F = m ( g+ [tex]\frac{v^2 }{2x }[/tex] )
Let's use kinematics to find the velocity of the person when reaching the floor
v² = v₀² - 2g (y + y₀)
the initial velocity is true and when reaching the ground y = 0
v² = -2 g (0-yo)
we calculate
v = [tex]\sqrt{2 ] 9.8 \ 0.800}[/tex]
v = - 3.96 m/s
the direction of this velocity is vertical down
let's calculate
a) x = 1.50 cm = 0.0150 m
F = 62.0 (3.96² / 2 0.0150 + 9.8)
F = 3.3 10⁴ N
b) x = 30 cm = 0.30 m
F = 62.0 (3.96² / 2 0.30 + 9.8)
F = 2.2 10³ N
c) to compare the force let's look for the relationship between the two
[tex]\frac{F_{rigid} }{ F_{flexible} }[/tex] = 3.3 10⁴ / 2.2 10³
\frac{F_{rigid} }{ F_{flexible} } = 15
therefore see that the force when rigid is 15 times greater than when bending the knees
An 8.20 kg object is pulled along a horizontal surface by a force of 22.0 N. If its acceleration is 1.1 m/s2, what is the coefficient of friction between the two surfaces?
Answer:
0.5
Explanation:
In this picture,
There is a bottleneck in producing masses higher than4He, because there are no mass-5or mass-8 stable nuclides. For older stars with high densities and high temperatures (T>100 million K), three alpha particles can form12C. This occurs by two alpha particles firstforming8Be, and then8Be reacting with another alpha particle to form12C before8Be candecay back to two alpha particles.a) Explain why this can only happen in very hot stars and high density.b) Calculate how much energy is given up when three alpha particles form12C.
Answer:
Explanation:
a)
To pass the Coulomb barriers and undergo nuclear fusion, alpha particles must be burned at high temperatures. As a result, the ignition temperature needed for this reaction is 5.4168 × 10¹⁰ K. Helium must be burned at a high temperature and density. As a result, this must occur for hot stars with high densities.
b)
The amount of energy given up can be calculated as follows:
[tex]_2He^4 + _2He^4 \to _4Be^8 ---- (1) \\ \\ _4Be^8 + 2_He^4 \to _6C^{12} ---(2)[/tex]
where;
[tex]M(_2He^4) = 4.002603 \ u \\ \\ M(_4Be^8) = 8.005305 10 \ u[/tex]
Therefore, from the reaction (1);
[tex]Q = \Big ( M(_2He^4) + M(_2He^4) - M(_4Be^8) \Big ) ( 931.5 \ MeV) \\ \\ = \Big ( 2(4.002603 \ u) - (8.00530510 \ u) \Big) \Big ( 931.5 \ MeV/u \Big) \ \\ \mathbf{= -0.092 \ MeV}[/tex]
From the second reaction:
[tex]Q = \Big ( M(_4Be^8) + M(_2He^4) - M(_6C^{12}) \Big ) ( 931.5 \ MeV) \\ \\ = \Big ( 8.00530510 \ u +4.002603 \ u -12 \ u \Big) \Big ( 931.5 \ MeV/u \Big) \ \\ \mathbf{= 7.37 \ MeV}[/tex]
A hunter on a frozen, essentially frictionless pond uses a rifle that shoots 4.20 gg bullets at 970 m/sm/s. The mass of the hunter (including his gun) is 69.5 kgkg, and the hunter holds tight to the gun after firing it. You may want to review (Page) . For related problemsolving tips and strategies, you may want to view a Video Tutor Solution of Collision along a straight line. Part A Find the recoil speed of the hunter if he fires the rifle horizontally.
Answer:
[tex]0.059\ \text{m/s}[/tex]
Explanation:
[tex]m_1[/tex] = Mass of bullet = 4.2 g
[tex]u_1[/tex] = Initial velocity of bullet = 0
[tex]m_2[/tex] = Mass of hunter with rifle = 69.5 kg
[tex]u_2[/tex] = Initial velocity of hunter with rifle
[tex]v_1[/tex] = Final velocity of the bullet = 970 m/s
[tex]v_2[/tex] = Final velocity of the hunter with the rifle
As the momentum of the system is conserved we have
[tex]m_1u_1+m_2u_2=m_1v_1+m_2v_2\\\Rightarrow v_2=\dfrac{m_1u_1+m_2u_2-m_1v_1}{m_2}\\\Rightarrow v_2=\dfrac{0-0-0.0042\times 970}{69.5}\\\Rightarrow v_2=-0.059\ \text{m/s}[/tex]
The recoil speed of the hunter is [tex]0.059\ \text{m/s}[/tex] in the opposite direction of the bullet.
Will give brainliest!!
If 30 grams of potassium chloride dissolved in 100 g of water at 70 o C, would the solution be saturated, unsaturated or supersaturated.
please help asap
Ms. Brando’s students are studying forces. She has assigned a fun task: designing a balloon car. The students must design a car and see which model will travel the greatest distance. The basic design of the cars can be seen here. First the balloon is inflated and attached to the car. It is important to keep the balloon closed. Once attached to the car, the stem of the balloon is opened and air rushes out through the straw. The air goes one way; the car moves in the other direction. There are no restrictions on the design other than the students must use the materials given to them by Ms. Brando. What is the source of the force that moves the car? A) The circumference of the balloons. B) The friction between the wheels and the track surface. C) The air rushing out of the balloon through the straw. D) The mass of the car: the lighter the car the farther it moves.
Answer: a
Explanation:
when a car dives on a road it a makes friction but it need something to push it or start it which is the balloon in this example
(sorry if im wrong)
A marble is placed at the bottom of a semi-spherical bowl, as shown in the figure. The marble is then displaced from the bottom of the bowl to a position about halfway from the top of the bowl. The marble is then released from rest such that the marble always remains in contact with the bowl. Students observe that the marble rolls back and forth as it oscillates about the bottom of the bowl. Which of the following statements best explains why the marble undergoes oscillatory motion?
a)The sides of the bowl become steeper at positions farther from the bottom of the bowl.b) The net force exerted on the marble always has a component directed toward the bottom of the bowl. c) The normal force exerted on the marble decreases with increasing distance from the bottom of the bowl. D ) The gravitational force exerted on the marble is constant in magnitude and direction.
Answer:
It is D
Explanation:
The explanation why the marble undergoes oscillatory motion should be option D.
What is oscillatory motion?An object should be classified as the motion oscillates related to an equilibrium position because of the restoring force or torque. This motion should be significant to study various phenomena like electromagnetic waves, molecules. etc. In the case when the gravitational force should be exerted on the marble here the magnitude and the direction should be the same.
learn more about the motion here: https://brainly.com/question/16335988
A 6.25 g quarter sits 25 cm from the axis of rotation on a turntable that has a period of rotation of 1.8 seconds.
What must the coefficient of static friction be in order to keep the quarter from sliding outward when the
turntable is in motion?
The coefficient of static friction be in order to keep the quarter from sliding outward when the turntable is in motion will be 0.31.
What is the friction force?It is a type of opposition force acting on the surface of the body that tries to oppose the motion of the body. its unit is Newton (N).
Mathematically it is defined as the product of the coefficient of friction and normal reaction.
On resolving the given force and acceleration in the different components and balancing the equation gets. The friction force balances centripetal force.
The given data in the problem will be;
m is the mass =6.25 g
r is the radius =25 cm=0.25 m
t is the time = 0.18 sec
μ is the coefficient of static friction =?
[tex]\rm F_c= mw^2r \\\\ f= \mu mg \\\\ F_C=f\\\\ mw^2r= \mu mg \\\\ \rm \mu = \frac{\omega^2r}{g} \\\\ \rm \mu = (\frac{2\pi}{1.8} )^2\frac{0.25}{9.81} \\\\ \rm \mu = 0.31[/tex]
Hence the coefficient of static friction will be 0.31.
To know more about friction force refer to the link;
https://brainly.com/question/1714663
Question 6.Why does a ball dropped from a certain height not bounce back 1 point
to the same height it was dropped from? *
Answer:
Because the coefficient of restitution is less than 1.
This coefficient is 1 for a perfectly elastic collision.
Some of the energy of the fall is absorbed by the ball so the ball cannot return to its original height.
Also, you have the effects of air resistance and some energy absorption of the the reflecting surface.