When your hand presses
down on scissors, what is your
force called?
a. input force
b. output force
c. buoyant force

Answers

Answer 1

Answer:

INPUT force

Explanation:

You are putting force into a machine of levers to have the output of cutting something.

Answer 2

When your hand presses down on scissors, the force is called input force because are applying a force into an object. Thus, option a is correct.

What is force ?

Force is an external agent acting on a body to deform it or to change its state from rest or motion. There are various kinds of force such as magnetic force, nuclear force, gravitational force etc.

Force is a vector quantity thus, it is characterised by a magnitude and direction. According to second law of motion, the force acting on a body is the product of mass and acceleration.

Hence, the force acting on a body is directly proportional to the mass. Greater the mass, greater will be the force needed to accelerate the body. When we press down on an object we are applying an input force to the object.

To find more on force, refer here:

https://brainly.com/question/28875770

#SPJ2


Related Questions

A length 550cm of thin thread wraps around a cylinder exactly 25 times calculate the circumference and the radius of the cylinder. ​

Answers

Answer:

3.5

Explanation:

hope it helps good day

kepler’s second law of planetary motion states ""a line from a planet to the sun sweeps over equal areas in equal intervals of ____.""

Answers

Kepler's second law of planetary motion states, 'a line from a planet to the sun sweeps out equal areas in equal intervals of time.'

What are Kepler's laws of planetary motion?

Kepler's three laws of planetary motion include

All planets orbit the sun in elliptical orbits with the sun as the focusA line from a planet to the sun sweeps out equal areas in equal intervals of timeThe square of the period of any planet is directly proprtional to the cube of the semi-major axis of its orbit.

From the second law, we see that, a line from a planet to the sun sweeps out equal areas in equal intervals of time.

So, Kepler's second law of planetary motion states, 'a line from a planet to the sun sweeps out equal areas in equal intervals of time.'

Learn more about Kepler's second law of planetary motion here:

https://brainly.com/question/25031109

#SPJ11

which of the numbers on this figure indicates typical continental conditions (regional metamorphism)?

Answers

The number that indicates typical continental conditions (regional metamorphism) is that showing schist and gneiss rocks.

What is regional metamorphism?

Regional metamorphism occurs when rocks undergoes changes as a result of high temperatures and pressure deep within the earth's crust.

Regional metamorphic rocks are usually foliated or squashed in appearance.

Examples of regional metamorphism rocks are schist and gneiss rocks.

Therefore, the figure that indicates typical continental conditions (regional metamorphism) is that showing schist and gneiss rocks.

Learn more about regional metamorphism at: https://brainly.com/question/14678538

#SPJ11

A 1.0-g string that is 0.64 m long is fixed at both ends and is under tension. This string produces a 100-Hz tone when it vibrates in the third harmonic. The speed of sound in air is 344 m/s. The tension in the string is closest to

Answers

The tension in the given string of 1.0 g and length of 0.64 m is closest to 2.84 N

Tension in the string

The tension in the string at nth harmonic is calculated as follows;

[tex]f_n = \frac{n}{2l} \sqrt{\frac{T}{\mu} }[/tex]

where;

n th harmonic = 3L is length of the string = 0.64 mμ is mass per unit length = (1 x 10⁻³ kg)/(0.64 m) = 0.00156 kg/mf is frequency = 100 HzT is tension in the string = ?

[tex]f_n = \frac{n}{2l} \sqrt{\frac{T}{\mu} }\\\\\frac{f_n(2l)}{n} = \sqrt{\frac{T}{\mu} }\\\\\frac{f_n^2(4l^2)}{n^2} = \frac{T}{\mu} \\\\T = \mu (\frac{f_n^2(4l^2)}{n^2})\\\\T = 0.00156(\frac{100^2 \times 4\times 0.64^2}{3^2} )\\\\T = 2.84 \ N[/tex]

Learn more about tension in string here: https://brainly.com/question/24994188

#SPJ1

help in solving this question please
(question is on the picture )

Answers

Answer:

Jesus

Explanation:

he is the way

3. Magnetite is
a) Natural magnet
(b)Artificial magnet
(c) Not a magnet ​

Answers

[tex] \huge \bold \red {Aɴswᴇʀ}[/tex]

Magnetite is a Natural magnet

the answer would be a magnetite is a natural magnet

A spring with a force constant of 3x10^3 Nm-1 is used to measure the mass of an object. If the spring extends by 5cm when the object is hung from it, the mass of the object is

Answers

Answer:

15.29 kg

Explanation:

F = k * d                  5cm = .05 m

 = 3 x 10^3  n/m     *   .05 m  = 150 N

                                                =  150 kg -m / s^2

150 kg- m / s^2   / 9.81 m/s^2 =15.29kg

Number 5 and 6 i need just give answer

Answers

Explanation:

voltage = current × resistance

5.

12 V = 4.2 A × resistance

resistance = 12 V / 4.2 A = 2.857142857... Ohm

FYI :

4.2 A would be a lot for a small electronic device like a CD player. that would be 12×4.2 = 50.4 Watt, and the CD player would get really hot.

6.

120 V = current × 12 Ohm

current = 120 V / 12 Ohm = 10 A

What type of reaction is being shown in this energy diagram?

A. Endothermic, because the reactants are higher in energy
B. Exothermic, because the products are higher in energy
C. Endothermic, because the products are higher in energy
D. Exothermic, because the reactants are higher in energy

Answers

[tex]\quad \huge \quad \quad \boxed{ \tt \:Answer }[/tex]

[tex]\qquad \tt \rightarrow \:Exothermic \:\;Reaction[/tex]

[ because reactants higher in energy ]

____________________________________

[tex] \large \tt Explanation \: : [/tex]

By the given graph, conclusion can be made that reactants have higher energy than products, hence for the reaction to take place, reactants must loose energy to form products. And once the energy is released, that reaction is called Exothermic.

Answered by : ❝ AǫᴜᴀWɪᴢ ❞

What local group of galaxies is the Milky Way part of?


Quasar Cluster


Andromeda Mini-Cluster


Virgo Supercluster


Hubble Open Cluster

Answers

The local group of galaxies which the Milky Way belong to is the Virgo Supercluster. C

What are Virgo Supercluster?

The Virgo Supercluster as known as the Local Supercluster is a mass concentration of galaxies that contains the Virgo Cluster and Local Group which in turn contains the Milky Way and Andromeda galaxies, as a host as others galaxies.

Therefore, the local group of galaxies which the Milky Way belong to is the Virgo Supercluster.

Learn more about Milky Way here:

https://brainly.com/question/1241789

#SPJ1

A rocket weighing 300,000 N is taking off from Earth with a total thrust of
460,000 N at an angle of 20 degrees, as shown in the image below. What is
the approximate vertical component of the net force that is moving the rocket
away from Earth?

Answers

Explanation:

vertical force = 460,000 * sin(70) - 300,000

Fv = 187,717.75N

When the light bulb is lit, a current is flowing through it. what condition must be met so that a current flows

Answers

Closed loop, conductor medium and presence of current in the wire are the conditions must be met so that a current flows.

What are the basic conditions for the flow of electric current?

The loop from where the current passes must be closed. There must be some current in the circuit in order to lit the bulb. The medium through which current flows should be a conductor.

So we can conclude that closed loop, conductor medium and presence of current in the wire are the conditions must be met so that a current flows.

Learn more about current here: https://brainly.com/question/24858512

#SPJ1

Eclipses and Moon Phases Activity Student sample of a modeled eclipse. This lesson highlighted eclipses and lunar phases. If you had to teach another person about the difference between the two events, how would you explain it

Answers

An eclipse is an event in which the sun or moon is blocked from view due to the presence of another celestial body, whereas lunar phases are caused by the reflection of the sunlight.

What is an eclipse?

An eclipse is an astronomical phenomenon where one celestial body (e.g., sun, moon) cannot be observed because another is interposed between the Earth and the first one.

Eclipses can be divided into moon eclipses (we cannot see the moon) and sun eclipses (we cannot see the sun).

On the other hand, moon phases occur due to how sunlight reflects the near side of the Moon.  

Moon phases can be divided into:

New MoonFirst QuarterThird QuarterFull Moon

In conclusion, an eclipse is an event in which the sun or moon is blocked from view due to the presence of another celestial body, whereas lunar phases are caused by the reflection of the sunlight.

Learn more about eclipses here:

https://brainly.com/question/8643

#SPJ1

Answer: the other person explained it all

Explanation:

solar power—generating facilities that generate electricity at large centralized facilities and transmit that power to homes and businesses through the electric grid are called ________.

Answers

Concentrated solar power facilities are solar powergenerating facilities that generate electricity at large centralized facilities and transmit that power to homes and businesses through the electric grid .

What is solar power?

Solar power refer to electric power or electricity that is generated from sun rays or radiations while using solar panels and other technologies.

Therefore, Concentrated solar power facilities solar powergenerating facilities that generate electricity at large centralized facilities and transmit that power to homes and businesses through the electric grid.

Learn more about solar power below

https://brainly.com/question/17711999

#SPJ12

A transverse wave that has electrical and magnetic properties is known as _________.
a. magnetism
b. loudness
c. electricity
d. electromagnetic energy

Answers

Answer:

D

Explanation:

the answer is D to me

the answer is D to me

The distance between slits on a diffraction grating is 0.60
How large is the path difference?
mm, and one of the angles of diffraction is 0.30°. The
light forms a second-order bright band.
O 1047 nm
• 1571 nm
© 3142 nm
6284 nm

Answers

The path difference is 1.57 × 10⁻⁶ m

Distance is the amount of space between things. From distance, it is the hard to tell if someone's wearing the a vampire costume abd just a chic black outfit.

For constructive interference thai is formation of bright fringe through a diffraction grating is given by:

d sin θ = n λ

here, d is the distance between slits.

θ is the angle of diffraction

n is the order of fringe

and λ is the path difference.

λ = (d sin θ)/ n = (0.60 *10 ⁻³m) (sin 0.30°) ÷ 2 = 1.57 * 10⁻⁶ m

Learn more about distance here

https://brainly.com/question/26550516

#SPJ10

Answer:

C is the answer

Explanation:

VR is always greater than MA. why?

Answers

Answer:

The mechanical advantage (M.A) of a real machine is always less than its velocity ratio(V.R) because mechanical advantage decreases due to the friction and weight of moving parts of the machine whereas the velocity ratio remains constant.

Describe the mass of the reactants and products given in the balanced chemical equation

Answers

When the chemical response is balanced, the mass of the reactant is equal to the mass of the reactant.

Grounded on the law of Conservation of Mass

We balance the chemical equation since tittles aren't destroyed in the process and the mass is conserved. The mass of the reactant is equal to the mass of the product. No new titles are created or destroyed, there was only rearrangement or regrouping of tittles. This also means the number of titles of rudiments in both the product and reactant is equal.

Learn more about mass conservation here:

https://brainly.com/question/2874230

#SPJ10

draw suitable diagrams where necessary
1. describe an experiment for the measurement of specific heat capacity of a liquid by principle of mixtures

Answers

The experiment is described below in the explanation.

What is specific heat?

The specific heat is the amount of heat required to change the temperature by 1°C. It is denoted by C.

Heat lost or gained is represented as

Q = m C ΔT

In a calorimeter, a liquid is filled into the the cup with a temperature. A rod with high temperature is inserted into that liquid.

We use principle of  mixture by putting a heated rod in a liquid and then measuring the rise of temperature of liquid.

So, heat is lost by rod and gained by liquid and colorimeter.

Thus, experiment is described.

Learn more about specific heat.

https://brainly.com/question/11297584

#SPJ1

When you attract every object in the universe with a force that is proportional to the mass of the objects and to the distance between them, you are obeying which law?

Answers

When you attract every object in the universe with a force that is proportional to the mass of the objects and to the distance between them, we are obeying Newton's law of universal gravitation.

Newton's law of universal gravitation

Newton's law of universal gravitation states that the force of attraction between two masses in the universe is directly proportional to the product of the masses and inversely proportional to the the square of the distance between them.

The mathematical interpretation of the above law is

F ∝Mm/r²

Removing the proportionality sign,

F = GMm/r².

Where:

F = Force of attractionG = Gravitational constantM = Bigger massm = Smaller mass r = Distance between the masses.

From the above, When you attract every object in the universe with a force that is proportional to the mass of the objects and to the distance between them, we are obeying Newton's law of universal gravitation.

Learn more about Newton's law of universal gravitation here: https://brainly.com/question/9373839

#SPJ12

3. State Newton's first and second laws of equation. A. A body of mass 2kg move vertically upwards has its velocity increased uniformly from 15m/s to 45m/s in 5s. neglecting air resistance, the upward vertical force acting on the body. [g=10ms 2] B. The velocity ratio and efficiency of pulley are 8 and 85% respectively. How much effort is required to lift a load of 120kg with this system [g=10m/s²] ​

Answers

Answer:

See below.

Explanation:

Newton's First Law

A body at rest persists in its state of rest, and a body in motion remains in constant motion along a straight line unless acted upon by an external force.

Newton's Second Law

A body's acceleration is directly proportional to the force exerted on it and is in the same direction as the force.  F=mA  (Force = Mass x Acceleration)

==============================================

A. A body of mass 2kg move vertically upwards has its velocity increased uniformly from 15m/s to 45m/s in 5s. neglecting air resistance, the upward vertical force acting on the body. [g=10ms 2] B. The velocity ratio and efficiency of pulley are 8 and 85% respectively. How much effort is required to lift a load of 120kg with this system [g=10m/s²] ​

Force = Mass x Acceleration

Acceleration is (45m/s - 15 m/s)/5 sec) or 6 m/sec^2

Force = 2kg*(6 m/sec^2)

Force = 12 kg*m/s^2    1 kg*m/s^2 is the SI unit for force, and is named 1 Newton(N), after . . . Newton.

Force = 12N

B.  I'm not sure how to interpret "The velocity ratio and efficiency of pulley are 8 and 85% respectively."  I'll assume "effort" is the energy required.  

I'll calculate the energy required in a perfect system, and then we'll consider the efficiency issues.

By lifting an object with mass off the Earth's surface (height = 0 meters) we impart a potential energy, PE, to the object.  This energy is stored in the object until it is allowed to move back closer to Earth.  This potential energy is given by the equation:

PE = mgh

where PE is potential energy in Joules, m is mass in kg, g is the acceleration due to Earth's gravity (9.8 m/sec^2, but we'll use 10 m/sec^2 as stated in the problem), and h is the vertical distance moved, in meters.

PE = (120kg)(10 m/sec^2)(h).  We aren't given a height, h.  Let's express the answer in terms of 1 meter:  How much potential energy is put into the 120kg load to raise it 1 meter?

PE = (120kg)(10 m/sec^2)(1 m)

PE = 1200 kg*m^2/sec^2 or 1200 kg*m/sec^2 per meter

The unit kg*m/sec^2 is 1 Joule

PE = 1200 Joules/meter

1200 Joules are required to raise 120kg 1 meter.  This is increased due to the less-tha-100% efficiency of 85%.

At 85% efficiency, the energy required would be 1200J/0.85 = 1412 J to raise 120kg 1 meter, with 85% efficiency,   I don't6 know how to handle the velocity ratio number.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                

all white dwarfs have masses in a small range—from about 0.5 to almost 1.4 malchemist sun symbol. why? (select all that apply.)

Answers

A white dwarf cannot support its own weight by its degenerate pressure if its mass is greater than 1.4 solar masses.

What are white dwarfs?

White dwarfs are stellar core remnant composed mostly of electron-degenerate matter.

White dwarf is very dense due to its large mass and smaller volume.

Reasons for comparable mass of white dwarfs and SunStars with main sequence masses less than about 0.5 solar masses cannot ignite the helium fusion required to become white dwarfs.A white dwarf cannot support its own weight by its degenerate pressure if its mass is greater than 1.4 solar masses.

Learn more about white dwarfs here: https://brainly.com/question/24873876

#SPJ11

1. When building a house using bricks a damp course is laid just above the brick foundation. Explain why the damp course is necessary​

Answers

Answer:

Damp Proofing:

Explanation:

The presence of damp proofing is very necessary to maintain the health of a structure. DPC plays an important role in all types of buildings and it should be necessary to know about the importance, requirements, and properties of DPC. In many of the buildings all over the world, the rising damp may be due to a damaged damp-proof course, or sometimes, there may be not any damp proof course in a building.

and electric motor lifts an elevator a vertical distance of 18.0m in a time of 30.0s by exerting an upward force of 6.0x10^3 N . what power does the electric motor produce?

Answers

Answer:

[tex]\fbox {3.6kW}[/tex]

Explanation:

Formula used :

[tex]\boxed {P = F \times v} \leftarrow \rightarrow \boxed {P = \frac{F \times S}{t}}[/tex]

Given :

⇒ F = 6 × 10³ N

⇒ S = 18 m

⇒ t = 30 s

Solving :

⇒ P = 6 × 10³ × 18 / 30

⇒ P = 2 × 100 × 18

⇒ P = 3600 W

⇒ P = 3.6kW

hello,help me with this out please i need it hurry but please ensure your answer is correct..I attach here with my question.
Topic:Forces in equilibrium.

Answers

Answer:

.409 N

Explanation:

For this to balance, the moments around the fulcrum must sum to zero.

On the left you have   .21   ( is that down? I will assume it is)

      Counterclockwise moments :

        .21 * 40     +  1.0 * 20    

     Clockwise moments :

        .5 * 20     +     F * 45

these moments must equal each other

.21*40 + 1 *20   =  .5 * 20 + F * 45

   F = .409 N

What is the kinetic energy of a 12 kg ball moving at a speed of 15 m/s?

Answers

Answer:

1350 N

Explanation:

KE = ½mv²

KE = ½(12)(15²)

KE = 1350 N

One of the properties of alkali metals is that they don’t react with water.

Answers

Beryllium (Be) is the only alkaline earth metal that does not react with water.

What are alkali metals and their properties?

Alkali is a substance that produces hydroxide ions in aqueous solution.

PHYSICAL PROPERTIES OF ALKALIS:

Alkalis have a BITTER taste & have a SOAPY touch.Alkalis turn RED litmus paper BLUE.Alkalis have a pH value > 7.Alkalis are CAUSTIC.Alkalis CONDUCT ELECTRICITY due to the presence of MOBILE IONS in solution.

CHEMICAL PROPERTIES OF ALKALI METAL

Alkalis react with Acids to form salt and water. This reaction is called neutralisation reaction.Alkalis react with ammonium salts to form salt, water and ammonia gas. .Alkalis react with solution of metal salt to form another metal salt and hydroxide.

Beryllium (Be) is the only alkaline earth metal that does not react with water.

learn more about alkali metal here: https://brainly.com/question/18153051

#SPJ1

A doctor has a patient blow on one side of a U-shaped tube that is partially filled with water and has a ball floating on the other side, as shown in the image below. If the ball rises with a force of 150 N, what pressure did the patient apply to his side of the tube?



A.
0.15 Pa

b.
150Pa

c.
100,000 Pa

D.
150,000 Pa

Answers

The patient apply pressure to his side of the tube is 15 x 10⁴ N/m². The correct option is D.

What is pressure?

The pressure is the amount of force applied per unit area. It is represented as

Pressure p = Force/Area

Given is a doctor has a patient blow on one side of a U-shaped tube that is partially filled with water and has a ball floating on the other side. The ball rises with a force of 150 N. The cross section are of the tube is 0.001 m³

The pressure applied is

p = 150 /0.001

p = 15 x 10⁴ N/m²

Hence, the patient apply pressure to his side of the tube is 15 x 10⁴ N/m².

Learn more about pressure.

https://brainly.com/question/12971272

#SPJ1

a ball is thrown upward from the ground with an initial velocity of 50m/s. what is the total time spent by the ball in the air (g=10m/s2)​

Answers

Answer:

[tex]\fbox {5 seconds}[/tex]

Explanation:

The formula which is used here :

[tex]\fbox {v = u + at}[/tex]

[tex]\longrightarrow \textsf {v : final velocity}[/tex]

[tex]\longrightarrow \textsf {u : initial velocity}[/tex]

[tex]\longrightarrow \textsf {a : acceleration}[/tex]

[tex]\longrightarrow \textsf {t : time taken}[/tex]

Solving :

v = u + at

0 = 50 + (-10)t

10t = 50

t = 5 seconds

what evidence would you expect to find on the moon if it had been subjected to plate tectonics? (select all that apply.)

Answers

Volcanoes and mountains are the evidences that show plate tectonics.

What evidence would you expect to find on the Moon if the Moon had been subjected to plate tectonics?

The presence of volcanos and mountains are the evidences that provides information that the moon has plate tectonic. If there is no volcanoes and mountains on the moon then we can say that there is no plate tectonic on the moon.

So we can conclude that volcanoes and mountains are the evidences that show plate tectonics.

Learn more about tectonics here: https://brainly.com/question/2325633

#SPJ11

Other Questions
There are 6.02 x 10^23 formula units Na2O in a sample. How many grams of Na2O is this? The molar mass of Na2O is about 62 g/mol. Alicia wants to model allopatric speciation for her science project. Shehas a population of ants to use as her model. What should she do tothe ant population?A introduce another species of ants to her populationBintroduce a new food source to part of her populationCplace a wall in their habitat that divides the populationDremove the water source from the population Separation anxiety disorder: Select one: a. Can be diagnosed at any age b. Should only be diagnosed well after normal separation anxiety is usually resolved c. Can be diagnosed in adults, even if the symptoms first appear in adulthood d. Both b and c are correct A sample of carbon dioxide gas occupies a volume of 250 mL at 25c what volume will it occupy at 95c ASAP ASAPWhich of the following is an example of Genetic Engineering?A. Mating the most productive plants together so their offspring will have a high yield.B. Altering the DNA of yeast to create vaccines.C. Raising pure breeds of dogs.D. Altering the chemical structure of alloys to create better characteristics. Can i use a 1000mAh battery instead of 600mAh Battery?please tell me quickly 23. (05.07 MC) Use the data in the table to determine the correlation coefficient. (1 point)Overall Student Average Math Class Average90 8095 9080 9084 9575 7580 850.650.350.300.03 (04.01, 04.02 HC)Eric plays basketball and volleyball for a total of 95 minutes every day. He plays basketball for 25 minutes longer than he plays volleyball.Part A: Write a pair of linear equations to show the relationship between the number of minutes Eric plays basketball (x) and the number of minutes he plays volleyball (y) every day. (5 points)Part B: How much time does Eric spend playing volleyball every day? Show your work. (3 points)Part C: Is it possible for Eric to have spent 35 minutes playing basketball if he plays for a total of exactly 95 minutes and plays basketball for 25 minutes longer than he plays volleyball? Explain your reasoning. (2 points) Which sentence below is a good example of "Expository Writing"? 4. in what ways do the activities of these organizations reflect the constitutional principles on which our government was created? discuss both organizations in developing your response. recall the six principles discussed in this course: popular sovereignty, republicanism, rule of law, limited government, federalism, and the separation of powers. (4 points), using the fbi and the nsa Which of the following did you include in your response? Check all of the boxes that apply. the range, or spread, of the salaries whether most people make a very low salary and one or two people make a high salary the minimum salary, and whether that is an entry level or starting salary the maximum salary whether the maximum salary is a lot higher than the average and other salaries are a lot lower than the mean What forces allowed the irish to be assimilated into u. S. Culture despite initial resistance?. Select all the correct answers.Pam is writing a literary analysis essay on Giovanni Boccaccio's story "Federigo's Falcon." Which two of the following should she include in the introduction paragraph of her essay?Even though Monna was unable to fulfill her dying son's wish, she found it in her heart to forgive Federigo after a period of mourning.An Italian writer and poet, Giovanni Boccaccio grew up in Florence. His mentor, the great poet Petrarch, translated Homer's Iliad and Odyssey at Boccaccio's request.Despite the tragic deaths of Monna's son and Federigo's falcon, Monna and Federigo find happiness with each other."Mother, if you can arrange for me to have Federigo's falcon, I think I would be well very soon." (Boccaccio)Giovanni Boccaccio's "Federigo's Falcon" is about Federigo, who is in love with Monna. He sacrifices his beloved falcon to prepare a meal fit for her, not knowing that she has come to request the falcon to save her dying son. Solve based off of the screenshot provided below. (2,6) and (12,2)? Write your answer in simplest form. Jacob traveled 171 miles in 3.8 hours. He wants to know how many miles he traveled in one hour, so he set up this problem: Use the formula to solve the equation x^2 + 9x + 8 = 0. A Complication or TwoWhich statement best explains the author's purpose?a)He wants to tell his children how much he loves them and uses a great deal of imagery to do so.b)He wants to share something he has learned about life and concludes the narrative with a life lesson.c)He wants to share something funny about his wife and includes many details about her.d)He wants to explain his career choice and provides many facts to support his decision. an excretory organ in our bod? algorithm to print the first 10 odd numbers