A farmer plants the same crop in a field year after year. Every year there are months during which the field is left without any plants. The farmer notices a decline in soil
quality during these months. What causes this decrease in soil quality?
Erosion
Drought
Desertification
Consumption of nutrients by the crops
Answers
Answer:
Drought
Explanation:
Related Questions
An ice cube in a glass of water is pushed to the bottom of the glass and held there with a straw. Consequently, the buoyant force on the ice cube is now a. the same as when the cube was floating at the top. b. exactly balanced by the weight of the ice cube. c. exactly balanced by the force exerted by the straw. d. greater than when the cube was floating at the top.
Answers
Answer:d
Explanation:
Given
Initially, the ice cube is floating over the water
When the cube is pressed to touch the bottom, it is submerged fully
Therefore more buoyant force is acting on it
At first, a part of the volume is submerged in the water, so the buoyant force is less, but as the entire cube is immersed in the water, the buoyant force increases.
Which of the following is an
example of thermal energy?
A. turning on a lamp so you can read
B. rubbing your hands together to get warm
C. kicking a ball
Answers
How much resistance is required to limit the current from a 12 V battery to 3.6 mA?
Answers
Answer:
3333.3 ohm
Explanation:
V=IR so R =V/I (in Ampere) so convert 3.6 mA to 3.6*10^-3 A
so R =12/3.6*10^-3 =3333.3
Newton's law of cooling states that the temperature of an object changes at a rate proportional to the difference between its temperature and that of its surroundings. Suppose that the temperature of a cup of coffee obeys Newton's law of cooling. If the coffee has a temperature of 185 degrees Fahrenheit when freshly poured, and 3 minutes later has cooled to 172 degrees in a room at 78 degrees, determine when the coffee reaches a temperature of 147 degrees.
Answers
Answer:
6.77 minutes
Explanation:
172 degree - 78 degree = (185 degree - 78 degree)e−2 k
=> 94 = 107
e−2 k => 94 ÷ 107
k => ln (94÷107) / 2
147 - 78 = (185 - 78)e ^[ln (94÷107) / 2]
=> 69 = 107 e^ [ln (94÷107) / 2]
e^[ln (94÷107) / 2] =69 ÷ 107
=> t = [ln (69 ÷ 107)] ÷ [ln (94÷107) / 2]
t=> -0.4387 ÷ -0.0648
t => 6.77 minutes.
Therefore, the final answer to the question is 6.77 minutes.
A capacitor with an initial potential difference of 100 V is discharged through a resistor when a switch between them is closed at t 0.At t 10.0 s, the potential difference across the capacitor is 1.00 V. (a) What is the time constant of the circuit
Answers
Answer:
τ = RC = 2.17 s
Explanation:
The voltage through a capacitor can't change instantaneously, so immediately after the switch is closed, the potential difference will keep at 100 V.This voltage will produce a flow of charge (a current) from the capacitor to the resistor, which will be diminishing continuously, till the capacitor be totally discharged, and the current becomes zero.The voltage through the capacitor will follow an exponential function of time, as follows:[tex]V_{C} =V_{o} * e^{-t/RC} (1)[/tex]
Replacing by the givens in (1):[tex]V_{C} = 1.00 V\\V_{o} = 100V\\t = 10.0 s[/tex]
[tex]\frac{1.00V}{100 V} = e^{-10s/RC} (2)[/tex]
Taking ln on both sides in (2), and solving for RC, we have:[tex]R*C= \frac{-10s}{ln 0.01} = 2.17s (3)[/tex]
So, the time constant of the circuit (the product of R times C) is equal to 2.17s.can someone help me with science:
The cells within a multicellular organism are of a uniform shape.
True
or False
Answers
Answer:
trur
Explanation:
gvidttcyhjddgdhjfjdjsjs
An electron is accelerated through a potential difference of 3.5 kV and directed into a region between two parallel plates separated by 29 mm with a potential difference of 100 V between them. The electron is moving perpendicular to the electric field when it enters the region between the plates. What magnetic field is necessary perpendicular to both the electron path and the electric field so that the electron travels in a straight line
Answers
Answer: [tex]0.985\times 10^{-4}\ T[/tex]
Explanation:
Given
Electron is accelerated 3.5 kV potential difference
Distance between plates d=29 mm
The potential difference between plates is V=100 V
here, the kinetic energy of an electron is acquired through a potential difference of 3.5 kV
[tex]\Rightarrow \dfrac{1}{2}m_ev^2=e\times 3.5\times 10^3\\\\\Rightarrow v=\sqrt{\dfrac{2\times 3.5\times 10^3e}{m_e}}=\sqrt{\dfrac{7\times 10^3\times 1.6\times 10^{-19}}{9.1\times 10^{-31}}}\\\\\Rightarrow v=\sqrt{1.23\times 10^{15}}=3.5\times 10^7\ m/s[/tex]
To move in a straight line Force due to magnetic field must be balanced by force due to charge
[tex]\Rightarrow F_B=F_q\\\\\Rightarrow evB=eE\\\\\Rightarrow B=\dfrac{E}{v}\\\\\Rightarrow B=\dfrac{\frac{V}{d}}{3.5\times 10^7}=\dfrac{\frac{100}{0.029}}{3.5\times 10^7}\\\\\Rightarrow B=\dfrac{3.448\times 10^3}{3.5\times 10^7}=0.985\times 10^{-4}\ T[/tex]
A vessel having a capacity of 0.05 m³ contains a mixture of saturated water an saturated steam at a temperature 245°C the mass of the liquid present is 10 kg. find the following: i- The pressure. ii- The mass. iii- The specific volume. iv- The specific enthalpy. v- The specific internal energy.
Answers
A 10 kg box initially at rest is pulled with a 50 N horizontal force for 4 m across a level surface. The force of friction acting on the box is a constant 20 N. How much work is done by the normal force pushing up on the box from the ground?
A. 10 J
B. 0 J
C. 100 J
D. 50 J
Answers
Answer: 0 j
Explanation:
It is given that,
Mass of the box, m = 10 kg
Force with which the box is pulled, F = 50 N
It is moved a distance of 4 m
Force of friction acting on the box, f = 20 N
We need to find the initial kinetic energy the box have. It is clear that the box is at rest initially. As there is no motion in the box at that time. The formula for the kinetic energy of the box is given by :
As v = 0
So, the initial kinetic energy of the box is 0. Hence, this is the required solution.
In Bohr's model, the position of the electron (with the monochromatic light on)... Group of answer choices is restricted to orbits or certain radii, but the electron may be observed between these orbits when it moves. is restricted to orbits of certain radii around the nucleus. The position may change, but it must be in one of these orbits. is not constrained. The electron may be found anywhere outside of the nucleus.
Answers
Answer:
True. it is restricted to the orbits of certain radii around the nucleus.
The position can change, but it must be in one of these orbits
Explanation:
In this exercise some affirmations are given and you must select which ones are correct, for this we review the Bohr atomic model that has the following postulates:
* the orbits are circular
* Only certain orbits are stable, stationary state
* the radiation emitted is the difference in energy between two stable orbits
* the size of the orbit is given by the quantization of the angular momentum
L = n [tex]\hbar[/tex]
When reviewing the different statements, the correct one is:
* it is restricted to the orbits of certain radii around the nucleus.
The position can change, but it must be in one of these orbits
Need help on question one ASAP pls help
Answers
Answer:
B
Explanation:
Because blocks 2 and 3 have sides with unequal forces while block 1 doesnt. Plz drop a follow if this helps! ❤
1. Describe the components of the reflex arc
Answers
30 POINTS PLS HELP NO LINKS PLS :/
In a wave, each particle of the medium vibrates, or oscillates, around a _____________.
A. Corner
B. Noise
C. Variable position
D. Fixed position
Answers
Answer:
C
Explanation:
trust me
D. Fixed position ,mean position , Equilibrium position.
What is wave motion?Wave motion is the transfer of energy and momentum from one point of the medium to another point of the medium without actual transport of matter between two points.
The particles of the medium vibrate about their equilibrium position in a direction parallel to the direction of propagation of the wave is called a longitudinal waves.
Characteristics of Wave Motion
In wave motion, the disturbance travels through the medium due to repeated periodic oscillations of the particles of the medium about their mean position (or) Equilibrium position.
Energy and momentum are transferred from one point to another without any actual transfer of the particles of the medium.
There is a regular phase difference between the particles of the medium because each particle receives disturbance little later than its preceding particle.
Therefore,
In a wave, each particle of the medium vibrates, or oscillates, around a fixed position.
Learn more about wave motion here:
https://brainly.com/question/12512349
#SPJ2
4. When scientists calculate the trajectory a satellite takes on its way to
study a planet, what do you think they use?
5 points
A Speed and velocity
B. Velocity and acceleration
O C. Speed, velocity, and acceleration
O D. Speed only
Answers
When scientists calculate the trajectory a satellite takes on its way to
study a planet, they use C. Speed, Velocity, and acceleration.
A trajectory, often known as a flight path, is the route taken by an object moving under the influence of gravity. Typically, the phrase is applied when referring to projectiles or satellites. A parabola curve is usually a decent approximation of the trajectory form when an object is propelled for in a short distance.
When scientists calculate the trajectory a satellite takes on its way to
study a planet they take the speed, velocity, and acceleration into consideration.
The formula for calculating the trajectory can be expressed as:
[tex]\mathbf{y = h + xtan (\alpha) - \dfrac{gx^2 }{2V_o^2cos^2 (\alpha)}}[/tex]
where;
h = height show the distanceV = velocityg = acceleration due to gravityLearn more about trajectory here:
https://brainly.com/question/88554?referrer=searchResults
Surface tension is often calculated using a machine that lifts a wire ring from the surface of a liquid. In this case the ring and liquid have some cohesive forces and attract rather than repel. In order to lift a ring of radius 2.75 cm off of the surface of a pool of blood plasma, a vertical force of 2.00*10-2 N greater than the weight of the ring is required. Consider the situation just before the ring breaks contact with the blood plasma where the blood plasma makes a contact angle of approximately zero degrees along the circumference of the ring and is stretched down vertically on both sides of the ring.
Required:
Calculate the surface tension of blood plasma from this information.
Answers
Answer:
0.116 N/m
Explanation:
Since the net force acting on the ring must be greater than 2.00 × 10⁻² N, and the surface tension T = F/L where F = net force = 2.00 × 10⁻² N and L = circumference of ring = 2πr where r = radius of ring = 2.75 cm = 2.75 × 10⁻² m.
So, T = F/L
= F/2πr
= 2.00 × 10⁻² N ÷ 2π(2.75 × 10⁻² m)
= 1/2.75π N/m
= 1/8.64 N/m
= 0.116 N/m
The plates of a vacuum-gap parallel plate capacitor have a 100.0 mm2 area, a vacuum gap of 5.00 mm and are connected to a 1.5-volt battery. After the capacitor is charged, the battery is disconnected from the capacitor. After the battery is disconnected, the plates are pulled apart until the vacuum gap is 7.50 mm. a. What are the initial and final energies stored in the capacitor
Answers
Answer:
E₀ = 2.0*10⁻¹¹ J = 0.2 pJ
Ef = 3.0*10⁻¹¹ J = 0.3 pJ
Explanation:
The energy stored between the plates of a parallel plate capacitor can be expressed in terms of the capacitance C and the potential difference between plates V as follows:[tex]E = \frac{1}{2} * C * V^{2} (1)[/tex]
When the capacitor is fully charged, the potential difference between plates must be equal to the voltage of the battery, 1.5 V.In a parallel plate capacitor, the value of the capacitance is independent of the applied voltage, and depends only on geometric constants and the dielectric constant of the medium between plates, as follows:[tex]C = \frac{\epsilon_{o}*A}{d} (2)[/tex]
We can find the initial value of C replacing in (2) by the givens below:A = 100.0 mm2d= 5.00 mmε₀ = 8.85*10⁻¹² F/m[tex]C_{o} = \frac{\epsilon_{o}*A}{d} = \frac{(8.85*(10)^{-12} F/m)*(10^{-4} m2)}{5.0*(10)^{-3}m} = 1.77*10^{-13} F (3)[/tex]With this value of C₀, and the value of the initial potential difference between plates (1.5 V), we can find the initial charge on the capacitor, starting from the definition of capacitance:[tex]C =\frac{Q}{V} (4)[/tex]Solving for Q in (4):[tex]Q = C_{o}* V = 1.77*10^{-13} F * 1.5 V = 2.65*10^{-13} C (5)[/tex]Finally, we can find the initial energy stored in the capacitor, replacing (3) and V in (1):[tex]E_{o} = \frac{1}{2} * C_{o} * V_{o} ^{2} = \frac{1}{2} * 1.77*10^{-13}F*(1.5V)^{2} = 0.2 pJ (6)[/tex]
If we pull apart the plates until the vacuum gap is 7.50 mm, we will change the expression of C in (2), decreasing its value due to the expanded gap.Replacing in (2) the new value of the gap (7.50 mm), we can find the new value of C, as follows:[tex]C = \frac{\epsilon_{o}*A}{d} = \frac{(8.85*10^{-12}F/m)*10^{-4} m2}{7.5*10^{-3}m} = 1.18*10^{-13} F (7)[/tex] In order to find the final energy stored in the capacitor, we need also the value of the final potential difference between plates.Once disconnected from the battery, the charge on any of the plates must remain the same, due to the principle of conservation of the charge.So, since we have the value of Q from (5) and the new value of C from (7), we can find the new potential difference between plates as follows:[tex]V_{f} = \frac{Q}{C_{f}} = \frac{2.7*10^{-13}C}{1.18*10^{-13}F} = 2.25 V (8)[/tex]With the values of Vf and Cf, we can find the value of the final energy stored in the capacitor, replacing these values in (1):[tex]E_{f} = \frac{1}{2} * C_{f} * V_{f} ^{2} = \frac{1}{2} * 1.18*10^{-13}F*(2.25V)^{2} = 0.3 pJ (9)[/tex]
A solid sphere of radius R, a solid cylinder of radius R, and a rod of length R all have the same mass, and all three are rotating with the same angular velocity The sphere is rotating around an axis through its center. The cylinder is rotating around its long axis, and the rod is rotating around an axis through its center but perpendicular to the rod. Which one has the greatest rotational kinetic energy? a. the sphere b. the cylinder c. the rod d. the rod and the cylinder have the same rotational kinetic energy e. they all have the same kinetic energy
Answers
Answer:
b. the cylinder
Explanation:
From the information given:
We understood that the mass of the sphere, cylinder, and rod length is the same with the same angular speed.
Taking their moments:
For the solid sphere; [tex]\text{The moment of inertia :}[/tex] [tex]I_s[/tex] = [tex]\dfrac{2}{5} \times m \times r^2[/tex]
The moment of inertia of the cylinder, [tex]I_c = 0.5\times m \times r^2[/tex]
The moment of inertia of rod, [tex]I_r =\dfrac{ m * r^2 }{12}[/tex]
The rotational kinetic energy is directly corresponding to the moment of inertia.
Thus, the cylinder has the greatest rotational kinetic energy.
An ant crawls in a straight line at a constant speed of 0.24 m/s for a distance of 3.0 m, beginning in the corner of a square classroom. It then turns exactly 90 degrees to the right, and proceeds an additional 4.0 m, reaching the far corner of the same wall from which it began. If the second leg of the journey was crawled in half the amount of time as the first, what was the ant's average speed for the whole trip?
Answers
Answer:
vavg = 0.37 m/s
Explanation:
The average speed is just the relationship between the total distance traveled, and the total time required for that travel , as follows:[tex]v_{avg} = \frac{\Delta x}{\Delta t} (1)[/tex]
We know that for the first leg of the journey, the ant crawls at a constant speed of 0.24 m/s, moving 3.0 m.We can find the time required for this part, just applying the definition of average velocity, and solving for the time t (which we will call t₁), as follows:[tex]t_{1} =\frac{x_{1}}{v_{1} } = \frac{3.0m}{0.24m/s} = 12.5 s (2)[/tex]
From the givens, we know that the time for the second part is exactly the half of the value found in (2), so we can write the total time Δt as follows:[tex]\Delta t = t_{1} + \frac{t_{1} }{2} = 12.5 s + 6.25 s = 18.75 s (3)[/tex]
We also know that in the second leg of the journey, the ant traveled 4.0 m, which adds to the 3.0 m of the first part, making a total distance of 7.0 m.Per definition of average speed, we can write the following expression as in (1) replacing Δx and Δt by their values, as follows:[tex]v_{avg} = \frac{\Delta x}{\Delta t} = \frac{7.0m}{18.75m} = 0.37 m/s (4)[/tex]
Based on the image which parachuter will fall fastest
A
B
Or C
Answers
Explanation:
c willl fall fast then a and b
How can parents help children to gain friends?
Answers
Answer:
You could try finding a familiar peer to join the activity with your child. Or ask your child who their friends are at school, or what they look for in a friend at school.
Answer:
Let the parents their Children to play outside
Explanation:
I HOPE I HELP YOU
A plano concave lens is one that has a surface that curves inward on one side and flat on the other, making the lens thinner at its center than at its edges. Its effect on light is :________
a. to diverge in incident eam of light
b. to make it appear as if incident parallel light is coming from a point close to the lens on the opposite side from the light source
c. to make it appear as if incident parallel light is coming from a point close to the lens on the same side as the light source
d. to converge light to a focus
Answers
Answer:
true statements are: A and C
Explanation:
In geometric optics, lenses are one of the most used elements, in general the curved surface, if they are convex, form real images, that is, the light rays have to converge at a point.
Concave lenses tend to create virtual images or I know that the extensions of the rays are what form the image.
The flat surface does not create changes in the image.
With these characteristics, let's examine the different true statements are: A and C
A) the rays diverge,
c) the rays parallel to the diverges their extensions are at a point on the same side of the lens this point is called focal length.
Why is the answer (A)?
In details please
Answers
Explanation:
resistance of wire can be determined by this equation
R = Rho . L / A
L = the length of wire
A = the Area, A = πr²
Rho = density of resictance
we can do some rational
R1/R2 = ( Rho L1/A1) / (Rho L2/A2)
L2 is the condition when the length is doubled and
L2 = 2 x L
A2 is the condition when the diameter is doubled
A2 = 4A1
R/R2 = (L1/A1)/(L2/A2)
R/R2 = (L/A) / (2L/4A)
R/R2 = 1 / ½
R2 = ½ R.
then we use formula of Voltage
V = I R
1st condition
V = 0.3 R
2nd condition ( V is constant)
V = I2 R2
0.3 R = I2 x ½R
i2 = 0.3/ ½
i2 = 0.6 Ampere
Background information:
We know that power is the rate that work is done; what that
really means is that power tells up how much work is done every
second. To calculate power we just divide the amount of work that
was done by the time it took to do it (Power=work/time). Work is
measured in Joules and time is measured in seconds, we end up with Joules/sec when we calculate power. A Joule/sec is a Watt; we’ll use Watts to measure and compare power.
We also know that the work done on an object is the amount of energy it has gained. For this activity, you’ll be raising your body up as you do pushups which means you’ll be giving your body gravitational potential energy (GPE). To calculate the amount of GPE we multiply mass time gravity times the height raised (GPE=mgh).
What to do (record everything in the table):
1. You need to have a decent estimate of your mass in kilograms: On earth, every
kilogram weighs 2.2 pounds. Either measure your weight on a scale or just
estimate it (in pounds) then divide by 2.2 to get your mass in kilograms.
2. Measure or estimate the length of your upper arm from your elbow to your
shoulder in centimeters...this is how high you raise yourself for every pushup.
3. Decide if you’ll do regular pushups (on your toes) or simpler pushups (knees). If
you are doing regular pushups, multiply your mass by 0.68 because you’ll only be lifting about 68% of your mass each time; if you’re doing simpler pushups, multiply your mass by 0.52 because you’ll only be lifting about 52% of your mass each time.
4. Measure the time it takes for you to do 10 pushups.
Answers
Answer:
Power is the rate at which work is done. It is the work/time ratio. Mathematically, it is computed using the following equation. The standard metric unit of power is the Watt.
Explanation:
What happens during rusting?
Answers
Answer:
when water hits a metal surface it alongside oxygen have a chemical reaction making Hydrogenated Iron Oxide
Explanation:
what i remember from 7th grade
Which of the following statements is NOT correct about sea breezes?
A) In a sea breeze, the sand is much warmer than the water, therefore creating a low pressure above the sand.
B) The breeze/wind moves from the sea to the land.
C) The breeze/wind moves from the land to the sea.
D) There is high pressure above the sea, and low pressure above the sand.
Answers
The breeze/wind moves from the land to the sea. This statement is NOT correct about sea breezes.
What is sea breeze?Local wind patterns known as sea breezes flow from the sea to land during the day. When there is no strong large-scale wind system and it is very hot or very cold during the day or at night, sea breezes and land breezes alternate along the coasts of large lakes or oceans.
Because the sea breeze's surface flow ends over land, an area of low-level air convergence is created. Locally, this convergence frequently causes air to rise, which promotes the formation of clouds. Showers over land in the afternoon may result from such clouds.
Hence, the sea breeze/wind moves from the land to the sea. This statement is NOT correct about sea breezes.
Learn more about sea breeze here:
https://brainly.com/question/13015619
#SPJ6
I need help with science o.o:
Question 1:
An egg yolk is unicellular.
True
False
___________________________
Question 2:
Your body has more than a billion cells.
True
False
_____________________
Question 3:
Almost all cells are not microscopic.
True
False
please dont steal my points :>
Answers
Answer:
TrueTrueFalseExplanation:
this is the answer
Answer:
1.true
2true
3.false
Explanation:
espero que te ayude
A 3.0-kg and a 1.0-kg box rest side-by-side on a smooth, level floor. A horizontal force of 32 N is applied to the 1.0-kg box pushing it against the 3.0-kg box, and, as a result, both boxes slide along the floor. How hard do the two boxes push against each other
Answers
Considering both boxes as one body, it would have a total mass of 4.0 kg. By Newton's second law, the 32 N force applies an acceleration a such that
∑ F = 32 N = (4.0 kg) a → a = 8.0 m/s²
and both boxes share this acceleration. (There is no friction, so the given force is the only one involved in the direction of the boxes' motion.)
Now consider just the smaller box. It is feeling the effect of the 32 N push in one direction and, as it comes into contact with the larger box, a normal force that points in the opposite direction. Let n be the magnitude of this normal force; this is what you want to find. By Newton's second law,
∑ F = 32 N - n = (1.0 kg) (8.0 m/s²)
n = 32 N - 8.0 N
n = 24 N
Just to make sure that this is consistent: by Newton's third law, the larger box feels the same force but pointing in the opposite direction. On the smaller box, n opposes the pushing force, so points backward. So from the larger box's perspective, n acts on it in the forward direction. This is the only force acting on the larger box, so Newton's second law gives
∑ F = 24 N = (3.0 kg) (8.0 m/s²)
If an object is placed between the focal point and twice the focal length of a convex lens, which type of image will be produced?
A.
real, upright, and magnified
B.
virtual, inverted, and smaller
C.
virtual, upright, and magnified
D.
real, inverted, and magnified
E.
real, upright, and smaller
Answers
Answer: I think its D
Explanation: Hope this was helpful...
A child makes a ramp to push his toy dump truck up to his sandbox. If he uses 5 newtons of force to push the 12-newton truck up the ramp, what is the mechanical advantage of his ramp?
Answers
Answer:
m = 2.4
Explanation:
Given that,
Input force, [tex]F_i=5\ N[/tex]
Output force, [tex]F_o=12\ N[/tex]
We need to find the mechanical advantage of the ramp. The ratio of output force to the input force is equal to mechanical advantage. So,
[tex]m=\dfrac{12}{5}\\\\m=2.4[/tex]
So, the mechanical advantage of his ramp is 2.4.
Brainliest!!! Write: Forces are all around us. Imagine that your teacher has asked you to teach a lesson to your peers about forces. Explain, in detail, how you experience forces in your everyday life. Give 3 examples
Answers
If you drag a bag across floor, you are experiencing a friction force
if you throw a paper or feather up, it floats side ways slowly. It is called air Resistance.
if you push or pull a Door, it is Normal force.
I hope this helped!
have an amazing Day!!