Elena

This page lists questions and answers that were posted by visitors named Elena.

Questions

The following questions were asked by visitors named Elena.

What is the best way to add fractions and reduced them to the lowest terms example 3/8+1/3+5/6

I am having a lot of trouble doing these types of problems. Can someone show me how to do this. Thank you for your time. Evaluate the definite integral 4 x(x+3)dx 0

17 years ago

Grade 7 question: I am a two-digit prime number I am one less than a multiple of 10 If you add 30 to me you get another prime number Who am I _________?

17 years ago

What is the balanced equation for ethane?

17 years ago

Mike is a sole shareholder of Cuteness Dog, Inc. (CDI). He is operating his company as a sub chapter S corporation. It is a small manufacturing company that produces a complete line of accessories for dogs such as collars, clothing, play toys, treats, etc...

16 years ago

It is a problem about the job-order costing used by a law firm.

15 years ago

3 elements that have the same properties most like Helium

15 years ago

describe how statistics can be important and influential in the nursing profession. Provide at least two examples where you have observed statistics to contribute positively to the needs of the customer.

14 years ago

You're given a ramp 0.5m in height with a 3m incline. A mass of 1kg is at the top of the ramp and there is a friction of 2N. If the ramp has a force of friction of 2N, what will the speed at the bottom of the ramp be?

14 years ago

find the derivative: d/dx int_a to x (a being the upper limit) of tan(tan(t))dt

14 years ago

Find the following interval: (2e^(2sqrt(y))/sqrt(y))

14 years ago

The distance required for an emergency stop for a car varies directly as the square of the car’s speed. A car traveling at 50 mph requires 140 feet to stop. What is the stopping distance for a car traveling at 30 mph? What is the stopping distance for a c...

13 years ago

The illumination provided by a car’s headlight varies inversely as the square of the distance from the headlight. If a headlight produces 15 footcandles at a distance of 20 feet, what will be the illumination at 40 feet? At 100 feet?

13 years ago

Prove these identites I really need help with these I don't understand how to do them !!!! sin^2+tan^2=sec^2-cos^2 sin^2 sec^2 +sin^2=tan^2+sin^2

13 years ago

Prove these identites I really need help with these I don't understand how to do them !!!! sin^2+tan^2=sec^2-cos^2 sin^2 sec^2 +sin^2=tan^2+sin^2

13 years ago

Solve for x and y X=1/6y Y=x-5

13 years ago

You have 40.00 g of ice at -20.0C. You want ot convert all the ice to steam at 140.0 C. How much energy will it take to do so?

13 years ago

Cloud seeding, which causes rain by introducing condensation into a cloud, has been used to bring precipitation to areas experiencing drought. Analyze the benefits and risks of cloud seeding.

13 years ago

Earth's axis tilts at an angle of 23.5 degrees relative to its orbit. Analyze the climate conditions that would exist at the poles and the equator if the axis were parallel to the orbit.

13 years ago

Why are space telescopes able to make better observations in the ultraviolet and infrared ranges than ground-based telescopes? A)space telescopes are closer to the objects that they are observing B) the atmosphere absorbs or reflects much of the UV and IR...

13 years ago

When was the telephone, atomic bomb, paper, flint tools, and the wheel invented? I've answered the other 4 and I think the telephone was invented in 1876. Please help.

13 years ago

Christine currently has $5000 in her 401(k) and plans to contribute $100 each month for the next 30 years into it. What will be the value of Christine's 402(k) in 30 years if the per annum rate of return is assumed to be 12% compounded monthly?

12 years ago

We are working on Passive and Active voice. i really don't understand it, so do you know any websites that could help me with passive and active voice.

12 years ago

we are learning about the 14 tenses: past,present,future,past perfect,present perfect, future perfect, past progressive..., past perfect progressive..., emphatic..and then there is another one but i forgot what that one was. Anyway, i need a website that...

12 years ago

Perform the indicated operations. Reduce the answers to lowest terms.... 1.) 7 3/5 + 2 4/7 = _______________ 2.) 8 5/9 + 15 5/6 =________________ 3.) 14 5/10 + 8 3/5 = ________________ 4.) 5/6 x 3/4 = _____________________ Reduce each fraction to lowest t...

12 years ago

Describe the differences you observe between the art and architecture of the Early Renaissance (Chapter 8) and that of the High and Late Renaissance. Select an Early Renaissance work of painting, sculpture, and architecture, and compare them to examples f...

12 years ago

0.25mol of CO are mixed with 0.90mol of H2 and heated to 950 degrees celcius in a 15L flask at equilibrium 0.190mol of H2O were present, what is the concentration of the other reactants and products at equilibrium and what is Kc

12 years ago

Eutrophication refers to 1. the concentration of a toxic substance in the tissues of organisms. 2. depletion of mineral resources as a result of leaching. 3. the warming of the earth’s surface. 4. the damage to the ozone layer that protects the earth from...

12 years ago

The eﬀect of humans on the environment is more drastic than that of other species because people have a greater ability to 1. adapt to seasonal changes. 2. learn new skills. 3. alter the environment. 4. eat diﬀerent types of food.

12 years ago

A small metal ball with a mass of m = 82.5 g is attached to a string of length l = 1.72 m. It is held at an angle of θ = 58.5° with respect to the vertical. The ball is then released. When the rope is vertical, the ball collides head-on and perfectly elas...

12 years ago

An object is placed 11 cm in front of a concave mirror whose focal length is 23 cm. The object is 3.6 cm tall. Determine (a) the location of the image, taking a real image as a positive value and a virtual image as a negative value. (b) Determine the heig...

12 years ago

A company has identified the following investments as looking promising. Each requires an initial investment of $1.2 million. Which is the best investment? a)a perpetuity that generates a cash flow at the end of year 1 of $100,000, has a growth rate of 1....

12 years ago

These are questions from Stephen King's collection "different seasons", particularly the novel "Rita Hayworth and the shawshank redemption": 1. From all the appearances the trial against Andy was pretty much "opens & shut". Identify the details that point...

12 years ago

1. True or False? A model train traveling at a constant speed around a circular track has a constant velocity. (False) 2.Which of the following would be affected if a soaring eagle changed direction but remained at a constant speed? acceleration only velo...

11 years ago

1. True or False: If the net force of an object is 0 N, the forces are considered unbalanced. (True) 2. Which of the following forces causes a feather to fall slower than a blowing ball? gravity ← rolling friction sliding friction air resistance 3. A smal...

11 years ago

1. r/5 = 9/21 r = 9 r = 2.14 r = 11.66 r = 37.8 2. A recipe calls for 3 cups of flour to make 3 dozen cookies. Use the proportion to calculate how much flour is needed to make 9 dozen cookies. 3cups/3dozen = xcups/9dozen 6 cups 3.5 cups 9 cups 12 cups 3....

11 years ago

the process in which body cells are duplicated in order to grow and repair body tissues is called

11 years ago

explain how to construct a perpendicular bisector

11 years ago

find sin2x, cos2x, and tan2x if sinx= -2/sqrt 5 and x terminates in quadrant III

11 years ago

Hector has $450 and saves 20 per week. Tim has $1200and spends $30 per week.write a system equation for this situation

11 years ago

Hello guys.I got a homework and seem like I am stocked. a)What type of experiments should be done to find the relationship between the strength of concrete and water/cement ratio. b)what will be the range of the water/cement ratio? It would be great if yo...

11 years ago

Consider two types of nonlinear equations. What unique quality does each possess and how does that quality cause the graph's unique shape? Name two unique examples of these shapes in real-world situations.

11 years ago

writers portray the personalities of characters A. only through revealing the characters private thoughts. B. through plot complication. C. only if the plot is not important to the story. D. through a variety of methods.

11 years ago

In "A Man Called Horse," After his wife leaves him, Yellow Robe Behaves recklessly in battle because he A. would rather die than live with the bitterness he feels as a result of his lost pride B. is trying to gain membership in the society known as the fo...

11 years ago

Use activity coefficients to find the concentration of hydrogen ions in a solution of 90.0 mM butanoic acid and 0.05 M NaCl. The ionization constant of butanoic acid is Ka = 1.52 × 10-5. Take the size of C3H7COO– to be 500 pm. How do I calculate the ionic...

11 years ago

I have an essay that says.. "It has been said that Eastern Europe is a political region more than a physical region. Would you agree or disagree with this statement? You must provide a solid argument for your position." since it asks me for my opinion how...

10 years ago

TRUE OR FALSE The burning of fossil fuels cause the earth to get warmer by putting carbon dioxide in the atmosphere and the carbon dioxide traps heat. MY GUESS: TRUE Isobars help meteorologists find fronts on weather maps. MY GUESS: FALSE A CLOUD IS A COL...

10 years ago

Smog is the worst in.. A. Chicago B. New York C. Los Angles MY GUESS: C. LOS ANGLES

10 years ago

The burning of fossil fuels cause the earth to get warmer by putting carbon dioxide in the atmosphere and the carbon dioxide traps heat. MY GUESS: TRUE

10 years ago

air pollution in pennsylvania causes ______ in new england because the wind blows the pollution into new England. can someone please help, I cant find this anywhere.

10 years ago

During the summer _________ in India, wet air from the Indian ocean brings heavy rain to India.

10 years ago

one reason the moon might be a better place than earth to study the universe is there is almost no atmosphere. True or False MY guess is false

10 years ago

the Julian calendar is the calendar we currently use. True or false. my guess is true

10 years ago

if x-7=14 what is the value of x-2 Can someone help me with this. I know the answer, I just want to know how something like this is solved.

10 years ago

If Jim is twice as old as Jerry plus six, Jerry is three years older than Tom, and Tom is 12, how old is Jim? I got = Jim is 36

10 years ago

Does the Commutative Property apply to this situation? I ate dinner and read a book. I got = Yes.

10 years ago

A 5.0 g n2o (laughing gas) that is inside a 12 mL cylinder used used to fill up a 800 mL whipped cream container. Beforehand, the container had air in it at 760 torr atmosphere pressure at 25 degrees celsius. Then, we will add the n2o/air mix to balloon u...

10 years ago

the charge on a pith ball was measured as +40 nC. if the charge on an electron is -1.6 x 10^-19, how many electrons have been added or removed from the ball?

10 years ago

Which relationship would most likely have a positive correlation? The amount of memory in computer, and the number of keys on the keyboard. The rate at which a train travels, and the time it takes for it to reach its destination. The number of tickets sol...

10 years ago

Is y=3x^2-2 a function? my guess is NO

10 years ago

the associative property allows you to change the order of terms in an expression. true or false my guess is True

10 years ago

classify the following number as rational or irrational: 4.1 My guess is Rational

10 years ago

An equation is not a function if even one x value produces ____ corresponding y value(s). one less than one more than one zero for a my guess is more

10 years ago

Does a machine that takes one quarter at a time into its input and produces one gumball in its output act like a function? my guess is YES

10 years ago

are the following a function 1. y=x/2 my guess is yes 2. y=2x+1 my guess is yes 3.y=x^2 my guess is yes 4.y=mx+b im not sure

10 years ago

Suppose we would like to estimate the mean amount of money spent on books by students in the fall semester. We have the following data from 400 randomly selected students: mean=$205 and s=$40. Assume that the amount spent on books by students is normally...

10 years ago

A criminologist is studying school violence, she selects a random sample of 25 adolescents aged 12 to 15 from a local middle school and asks the following,"How many times within the past school year have you been physically assaulted at school? She calcul...

10 years ago

How were each of the following cations utimately separated from the rest of the group and /or decorated? The use of equations may be helpful, where applicable. Ag+ K+ Nh4+ Al+

9 years ago

How were each of the following cations utimately separated from the rest of the group and /or decorated? The use of equations may be helpful, where applicable. Ag+ K+ Nh4+ Al+

9 years ago

If vector a= (10,10) and vector b= (4,5) then ||a+b|| ≠ ||a|| + ||b||. Explain. I don't understand what this question is exactly asking, and I'm not sure how to answer it. Please explain. Thank you very much!!!

9 years ago

1. What is the heat required in kilocalories to convert 2 kg of ice at 0°C completely into steam at 100°C? (I thought it was 2000 kilo cals but I think I'm wrong??) a. 80 Calories b. 1440 Calories c. 4186 Calories d. 540 Calories 2. A gaseous refrigerant...

9 years ago

Which sentence has correct subject - verb agreement a) casey or robbie are coming to the movies with us b) swimming and skiing is my favorite sports c) sandwhiches or pizza both sounds good for a quick dinner** d) either your brother or his friend is maki...

9 years ago

Under a spreading chestnut tree which syllables are unstressed?

9 years ago

Which statement best demonstrates why the following is a non-example of a polynomial? 33/16 - 62y^2xz-35z^1/3y^2 a. The expression has a variable raised to a negative exponent. b. The expression has a variable in the denominator of a fraction. c. The expr...

9 years ago

What mass of sodium has the same number of atoms as 50.0 g of calcium?

8 years ago

Match the question with the correct conversion factor needed. Column A 1.What is the mass, in grams, of a single atom of carbon?: 2.What is the mass, in grams, of a single atom of iron?: 3.What is the mass, in grams, of a single molecule of water?: 4.What...

8 years ago

You and 4 friends go to a concert. In how many different ways can you sit in the assigned seats? 20 24 48 120 I think its A im not to sure

6 years ago

What was a symbol representing gold, silver, and the government's promise to pay? paper currency a tariff a trust a railroad

5 years ago

Which event resulted from the company cut the workers' wage five times, but not cutting their expenses, leading to terrible violence resulted when federal troops came? the creation of the Populist Party the first breakup of a trust by the government the d...

5 years ago

Are these statements true or false? The Republican were voted into power and presided over the government at the beginning of the twentieth century. They favored a more limited democracy, with decision-making power in the hands of the elected or appointed...

5 years ago

Is this statement true or false? The federal government was responsible for keeping the monetary supply sound, protecting businesses during strikes, and aiding unemployed workers in the late 1800s. true false

5 years ago

Farming in the United States change in the late 1800s in all of the following ways EXCEPT: World competition decreased. Farmers used new equipment. Larger farms produced a single crop. The amount of money in circulation increased.

5 years ago

At what pH should precipitate Ni(OH)2 from 1 solution containing ions Ni2+ with concentration 0.2 M? KPT Mg(OH)2=5×10-¹⁶

5 years ago

A solution prepared by dissolving 10 grams of HF in 500 grams of water, freezes at a temperature of -1.98 ° C. Calculate the pH of this solution and the dissolution constant of the HF acid solution with density d = 1.05 g / mL. (Freezing constant = - 1.86...

5 years ago

Represents all structures for alkenes and cycloalkenes with formula C6H10. Indicate which of the structures represent geometric isomers.

5 years ago

The number 11,p,q,21¹/2.....form an A.P. Find p and q

4 years ago

Keiko is riding a skateboard 2 m/s, west. How long will it take her to reach a velocity of 8 m/s, west if her acceleration is 2 m/s2? 3 seconds 6 seconds 8 seconds 10 seconds

4 years ago

Town X and Town Y were 980 km apart. At 8 a.m, Kay traveled from town X to Town Y while Jolin traveled from town Y to Town X. Bothe of them did not change their speeds throughout their journeys. Jolin's speed was 75 km/h. Find the distance Kay traveled wh...

4 years ago

(Cr2O7)2- + 2Al + 14H+ <—> 2Cr3+ + 2Al3++ 7H2O 1) how many ml of solution 1.50 M e (Cr2O7)2- are needed to act without residue with 0.8 grams of Al? 2) what is the concentration of the solution (Cr2O7)2-

4 years ago

What is the volume of a square pyramid that is built in a cube with edges of 12 in

2 years ago

What is the volume of a square pyramid with base edges of 4 ft and a hight of 15

2 years ago

What's the volume of a cone with a radius of 6 m and height of 20 m

2 years ago

What's the volume of a pyramid with the base area of 24.3 cm and a height of 14 cm

2 years ago

What is the volume of a prison with base area of 24.3 cm and a height of 14 cm

2 years ago

Is the volume of a cone with a base radius of 4 in and height of 3 in

2 years ago

What is the volume of a cone with the base radius of 3 and a height of 4 in

2 years ago

What's the lateral area of a cone with a radius of 7 ft and a slant height of 13 ft used 3.14 for pi and round to the nearest ten

2 years ago

Answers

The following answers were posted by visitors named Elena.

v(x0) =v(x)=8 m/s v(y0) =0 v(y)=gt=10•3.8=38 m/s v=sqrt{v(x)² +v(y)²} = =sqrt (8²+38²) = 38.8 m/s

12 years ago

p1V1 =p2V2 V2=p1V1/p2 d. 0.25 m^3

12 years ago

101325/100=1013 Pa, 1013•1.8 =1.8•10^3 N

13 years ago

p=sqrt{p(x)² +p(y)²} = = sqrt(98² +100²)=140 kg•m/s

13 years ago

F(net) = F-F(res) =(2.06-1.75)•10³=0.31•10³=310 N a=F(net)/m= 310/1300=0.24 m/s² s=at²/2=… v=at = …

12 years ago

W=q•Δφ q= W/Δφ=4.5•10⁻⁴/(300-150)= 3•10⁻⁶C Since this motion takes energy q= - 3•10⁻⁶C

12 years ago

v=ωR=2.08•0.25 =… (m/s)

12 years ago

List 3 physical activities in which the human body engages in movement.Next:Determine which bones are involved in these movements.

17 years ago

s = [(v(fin) ² -v(init)²]/2•a

13 years ago

your adding the total number students from each class. 21 + 32 = 53

17 years ago

3 different ways feed them one at a time feed them two at a time feed them all at the same time

17 years ago

Thank You !

17 years ago

STP =standard temperature and pressure: T= 273.15 K p=10⁵Pa μ for hydrogen =2 g/mol= 0.002 kg/mol R=8.31 J/mol•K. m=1g=0.001 kg From pV=mRT/μ V= mRT/μp

12 years ago

I'm having trouble researching a topic pertaining to European weaponry in the late 16th and early 17th centuries. I would greatly appreciate any recommended resources, preferably online.

16 years ago

d. the momentum of smaller mass body is larger than the other

13 years ago

n=3390 rev/min=3390/60 rev/s D= 0.52 m R= 0.26 m. v=ω•R =2•π•n•R= 2• π•339•0.26/6 =92.3 m/s, ω (fin)= ω - ε•t. ω (fin)=0, ε = ω /t = 339/6•3 =18.8 rad/s²

13 years ago

For max height : mvₒ²/2 = m•g•H, Initial velocity vₒ=sqrt(2•g•H) = sqrt(2•9.8•120)=48.5 m/s. mvₒ²/2 = mgh + mv²/2, mv²/2 = mvₒ²/2 – mgh = =m•g•H -0.75 m•g•H=0.25 m•g•H mv²/2=0.25mgH v =sqrt(2•0.25•g•H) = sqrt(0.5•9.8•120)=24.2 m/s. h =(vₒ²-v²)/2•g =(48.5²...

13 years ago

H=D+h= 14.6+2.4 =17 m. H=gt²/2 t=sqrt(2H/g) =sqrt(2•17/9.8)=1.86 s. v(x) =1 m/s. L=v(x) •t=1•1.86 = 1.86 m.

13 years ago

There are 3,500 calories in one pound of fat, according to the American Heart Association.

13 years ago

1 Identify a Problem/Condition Affecting Your Quality of Life 2 Identify the Negative Health-Related Behavior 3 Identify Your Behavior Change Goal for the Project 4 Establish Your 7- Week Action Plan 5 Identify Potential Negative Influences and Possible S...

13 years ago

μ •m•g =m•v²/2 v=sqrt(μ• g •R)

13 years ago

T(max) = mv²/R. v=sqrt(R•T(max)/m) = =sqrt(2•75/0.4)=19.4 m/s

13 years ago

teacher: v1=0.67 m/s, river: v2 =1.4 m/s, v=sqrt(v1²+v2²) =1.55 m/s. (to the east of south) L =175 m, s=? v/v1=s/L => s= v•L/v1 =1.55•175/0.67 =404 m. t=s/v =404/1.55 =260 s =4.34 min

How can I get the answer for Milestone 3,4,5, Situation Parent, Inc. is contemplating a tender offer to acquire 80 percent of Subsidiary Corporation's common stock. Subsidiary's shares are currently quoted on the New York Stock Exchange at $85 per share....

13 years ago

T1=2π•sqrt(L/g) T2=2π•sqrt(L/0.31g) T2=T1/sqrt(0.31)=0.7/0.557=1.26 s.

13 years ago

According to the Law of conservation of linear momentum for the inelastic collision m1v=(m1+m2)u. Then u=m1v/m1+m2=(0.13x40)/0.4=13 m/s

13 years ago

F=ma=m(v2-v1)/t=0.35(12-0)/0.30=14 N

13 years ago

F=ma=mΔv/Δt=m(v2-v1)/Δt As v1=0 v2=FΔt/m=32.5x0.16/0.126=41.3m/s

13 years ago

Thanks DrBob222, I think I can figure this out now. I didn't know quite how to tackle this -- I appreciate it!

13 years ago

According to the Law of conservation of angular momentum L1= L2, I1•ω1=I2•ω2. ω1=2πn1 ω2=2πn2 I2=I1/3. Then n2=(I1/I2)n1=3•2=6 s-1

13 years ago

1. For accelerated motion s=v0t+(at2/2) and v=v0 + at Since initial velocity v0 is zero, s=at2/2 and v= at. t=v/a=15/1=15 s. s=1•225/2=112.5 m. 2. If s =at2/2 = 100 m, t=sqroot(2s/a)= sqroot(2•100/1)=14.14 s. v=at=1•14.14=14.14 m/s.

13 years ago

The torque acting on the dipole in electric field of strength E= 1400 V/m (!!!!- units) is M=F•(d/2), where d=12 cm and F=qE. From mechanics (Newton’s second law for rotation) M=I•ε, where I=(md^2)/12 is the moment of inertia of the rod about the axis pas...

13 years ago

X-component of the package velocity on the instant when it begins the motion is vx= vcosα=76.8cos48^0=51.4m/s. The description of this projectile motion is x=vxt y=(gt^2)/2, the time of motion is t=sqroot(2y/g)=10.7 s, then the distance along the ground,...

13 years ago

The torques have be equaled P1x=P2(2.2-x) x=(P2•2.2)/( P1+ P2)=0.4 m Part 2 P1•0.4+P3(0.4-0.193) = P2•1.8+P4•x, P4 where P1=450.8 N, P2=101.0 N, P3= 367 N, and P4=261 N. Calculate x

13 years ago

Where is the question?

13 years ago

1. s1=(2πR)/4=392.7 m 2. d1=250•sqroot(2)=353.6 m 3. s2=(2πR)/2=785.4 m 4. d2=2R=500 m 5 s3=2πR=1571 m 6. d3=0

13 years ago

For each cylinder mgh=(mv^2)/2+(Iω^2)/2 =(mv^2)/2+(Iv^2)/2R^2. For hallow cylinder the moment of inertia is I=mR^2, and for solid cylinder I=(mR^2)/2. Therefore, the velocities at the bottom are - for hallow cylinder v=sqroot(gh), - for solid cylinder v=s...

13 years ago

Let the charge q1 be in left bottom corner, then clockwise q2 and q3, and q4 =10microC in the center. The forces F14=F34. The force F24=1/(4πε0)•(q2q4)/r2, where r=a/sqroot2=58mm/ 1.41=38.9 mm=0.0389 m. F24=(9•10^9)•(4•10^-6•10•10^-6)/(0.0389)^2=142.7N

13 years ago

The mailbag moves upwards with the initial velocity v0=2 m/s. Its motion is decelerated h = v0t - (gt^2)/2 v = v0 - gt. If v=0, v0=gt and t = v0/g = 2/9.8=0.2 s. h = 2•0.2-(9.8•0.04)/2 = 0.204 m Helicopter moves uniformly, therefore, H = vt = 2•0.2 = 0.4...

13 years ago

The horizontal motion is with uniform speed vx=v0•cos33=40•0.84=33.55m/s t=(2v0sinα)/g=2•40•0.54/9.8=4.45 s

13 years ago

The case of inelastic collision m1•v1+m2•0=(m1+m2)•v v= (m1•v1)/ (m1+m2). It is necessary to know the mass of a piece of wood m2. The change in kinetic energy is ΔK=K1-K2 = m1(v1)^2/2 - (m1+m2)v^2/2. For finding the percentage ((K1-K2)/K1) •100%

13 years ago

λ=vT=v/f f= v/λ=1 x 10^5 /1 x 10^5 =1 Hz

13 years ago

If the energy is reduced by 40%, then 60% is left. Therefore, PE = mgH = KE (at hitting the ground). Upward motion 0.6KE=0.6mgH = mgh. Then h=0.6x10=6 m.

13 years ago

After leaving the helicopter the package is moving upwards at the initial velocity v0. This is decelerated motion with acceleration –g (g≈10m/s^2) h0=v0t1-(gt^2)/2 v=0=v0-gt1 t1=v0/g=20/10=2 s. After this time interval the package is at the height h0=v0^2...

13 years ago

The distance covered by speeder (uniform motion) is s=vt The same distance covered by policeman (accelerated motion from rest) is s=(at^2)/2. From vt=(at^2)/2 t=2v/a=2•38/2.03=37.4 s.

13 years ago

F=mg=2•9.8=19.6 N From Newton’s 2 Law a=F/m= 19.6/4.9=4 m/s^2. s=(at^2)/2=(4•4)/2=8 m.

13 years ago

The work is equal to the change of kinetic energy W=ΔK=K2-K1= 0-(mv^2)/2 W=0.168•(11.4)^2/2=10.9 J.

13 years ago

You have to know the radius of curvature R as the distance is s=vt=ωRt, where ω is the angular velocity

13 years ago

Since the reaction time of the driver is t1, therefore the automobile, during this time, will continue to move with uniform velocity v1. Distance covered during t1 is s1=v1•t1. After this the automobile begins to decelerate. Relationship between initial v...

13 years ago

The magnitude of torque is M=p•B•sinα, where p is the magnetic moment, B is magnetic field. Max M=p•B. p=I•A, where A is the area of the loop. If the length of the wire is L=2πR, the radius is R=L/2π, the area is A= πR^2=L^2/4 π=1.626•10-4 (m^2) Max M= I•...

13 years ago

The range of projectile is L=(v0)^2•sin2α/g. If α=45 degr, sin2α = 1, then L=v0^2/g. v0=sqroot(L•g)= sqroot(90•9.8)= 29.7 m/s

13 years ago

The ball after leaving the table takes part in two motions: horizontal uniform motion L = v(hor) •t, and vertical free fall H = gt^2/2, t = sqroot(2H/g) = sqroot(2•0.7/9.8) = 1.43 s. v(vert) = gt = 9.8•1.43 = 14 m/s. tan α = v(vert)/ v(hor)=14/6.4=2.19 α...

13 years ago

SORRY! t = sqroot(2H/g) = sqroot(2•0.7/9.8) = 0.143 s. v(vert) = gt = 9.8•0.143 = 1.4 m/s. tan α = v(vert)/ v(hor)=1.4/6.4=0.219 α = 12.35 degr

13 years ago

The ball after leaving the table takes part in two motions: horizontal uniform motion L = v(hor) •t, and vertical free fall H = gt^2/2, t = sqroot(2H/g) = sqroot(2•1/9.8) = 0.2 s. L = v(hor) •t = 4.4•0.2=0.88 m.

13 years ago

27 feet = 8.23 m PE =KE, mgH = mv^2/2 v=sqroot(2gH)= 12.7 m/s. If the collision with the ground is elastic, the height of the ball would be equal to its initial height. It cant reach the heigth of 15 m.

13 years ago

Potential energy of the charges is PE=k•q^2/r=9 •10^9•(9•10^-6)^2/0.052=14 Joules. According to the Law of conservation of energy PE=2KE KE=mv^2/2. 2KE= mv^2 =PE v=sqroot(PE/m)=sqroot(14/10^-3)=118.3 m/s.

13 years ago

The sound velocity depends on temperature as v (meters per second)=20.046•sqroot(T) where T is absolute temperature (in Kelvins), or v(meters per second) = 331.4+0.6•t, where t is the temperature in degrees centigrade 100F = 37.78 degrC v = 331.4+0.6 •37....

13 years ago

KE2 - KE1= A(friction). KE2 - KE1=0-(m•v^2)/2= - (m•v^2)/2. A(friction) = F(friction)•s•cosα = k•m•g•s•(-1) = - k•m•g•s. (m•v^2)/2= k•m•g•s. v=sqroot (2•k•g•s)= =sqroot (2•0.05•9.8•22.3)=21.85 m/s.

13 years ago

The work done by the pulling force is A = F •s •cos α = 279•9.14•cos26.3° = 2286.1 Joules. The work done by the kinetic frictional force is Afr = Ffr •s •cos α =kmgscos180°= =0.259•75.9•9,8•(-1)= - 195.6.

13 years ago

A= KE2 - KE1= (mv2^2)/2 - (mv1^2)/2 =2058.6 J.

13 years ago

KE2=0.37KE1 (m(v2)^2)/2=0.37(m(v1)^2)/2. The speed of the ball immediately after rebounding is v2=v1(sqroot(0.37)) =0.6•7=4.2 m/s. The magnitude of the impulse of the ball on the wall: delta(p) = p2 - p1= mv2 - (- mv1) = mv2 + mv1= m(v2+ v1) = 0.22•(4.2 +...

13 years ago

a. ω = v/R = 3.6/0.435 = 8.28 rad/s2 b. From kinematics: s = v0 - a•t^2/2 v = v0 + a•t. Since v0 = 0, a = v^2/2•s = = ( 3.6)^2/2•4 = 1.62 m/s2. Second law: m•a = m•g – T, T = m•g - m•a= 18(9.8-1.62) =147.24 N. The second law for rotation: I•ε = M I• (a/R)...

13 years ago

Both wheels have the same linear speed v=ω1•r1= ω2•r2 Taking into account that ω1=ε•t, ω2= 2•π•n=(2•π•52.9)/60 (rad/s) ε•t•r1=(2•π•52.9/60)•r2 t= (ω2•r2)/ε•r1=(ω2•r2)/(2•π•52.9/60)•r2 =2.29 s.

13 years ago

U=-2mgh/3

13 years ago

According to the law of conservation of linear momentum vector(p)= vector(p1)+ vector(p2), Let vector( p) is directed along +x-axis. Then vector (p1) is below x-axis and vector(p2) is above it. Projections on axes are x: v = v1•cosα +v2•cosβ y: 0 = - v1•s...

13 years ago

C) A can of ice It has the constant location of center of mass

13 years ago

PE=KE (if there is no friction) mgh=mv^2/2 v=sqroot(2gh)

13 years ago

F = I •L•B• sinα If this wire is at right angles to Magnetic field, sinα = 1, then I=F/L•B=0.2/453•2.56 =1.76•10^-4 (A)= 0.176 mA.

13 years ago

KE = PE KE = mgh = 1•9.8•0.04 = 0.392 J.

13 years ago

Compressive stress is F/A F=mg=70•9.8=686 N A=πR^2-πr^2=π(R^2-r^2)= =3.14(12.25-6.25)•10^-4= =18.84•10^-4 (m^2) sigma = F/A=364118 (N/m^2)

13 years ago

Where is the question?

13 years ago

T=1/f=1/440=0.00227 s.

13 years ago

ΔKE = - ΔPE mv^2/2 - 0=-(mgh-mgH) mv^2/2=mg(H-h)=mg(H-H/2)=mgH/2 v=sqr(gH)=sqr(9.8•1.8) =4.2 m/s

13 years ago

Wavelength LAMBDA= Light speed/Frequency = 3x10^8/540x100 = ....

13 years ago

F•cosα=Ffriction=k•mg F=kmg/cosα=0.57•32•9,8/cos 21 =191 N

13 years ago

F=ma

13 years ago

x = Acosωt v = - Aωsinωt a= - Aω^2cosωt a/x= Aω^2cosωt/ Acosωt=ω^2 = 16 ω= 4 (rad/s) T=2π/ω=2π/4 = π/2 = 1.57 s.

13 years ago

F=G(m1xm2)/r^2= =6.67•10^-11•(6•10^24•2•10^30)/(1.5•10^11)^1=3.56•10^22 N

13 years ago

F=k•(q1•q2)/r^2=9•10^9•(4•10^-6•6•10^-6)/(0.45)^2=1.067N

13 years ago

The motion of jumping person is similar to projectile motion: H=(Vo)^2•(sinα)^2/2g L=(Vo)^2•(sin2α)/2g= =(Vo)^2•(2sinα•cosα)/2g. 2H/L=sinα/cosα, tanα=2H/L=21.23/2=1.23 α=arctan1.23=50.9° Vo=sqr(2gH)/ sinα=6.33 m/s. t=2Vo•sinα/g=1 s.

13 years ago

p=ρgh=1000(kg/m3)•9.8•100=9.8•10^5 N/m2

13 years ago

Law of Archimedes:The buoyant force is equal to the weight of the replaced water or gas. Weight of replaced water is mg=ρ•V•g= ρ•a^3•g=1025•1•9.8=10045 N (ρ is the density of sea water)

13 years ago

Kinetic energy = work of resistive force mv^2/2= W= F•s•cosα cosα = 1 F= mv^2/2•s=0.03•(200)^2/2•0.12=5000 N

13 years ago

For upward decelerated motion v=Vo-gt Since v=0, Vo=gt. Let g= 10 m/s2, t=Vo/g=30/10=3 s. h=Vo•t-(gt^2)/2 = =30•3-10•9/2=45 m. Total height H=45+80=125 m. H=gt^2/2, t=sqroot(2H/g)=sqroot (2•125/10)=5 s.

13 years ago

If the mass of the Galaxy is all at the center the angular velocity at distance R is given by ω = sqr(M•G/R^3), where M = central mass kg, G = gravitational constant 6.67 x 10-11 Nm2kg-2, R = distance from central mass m

13 years ago

The angle XYZ = 135o According to the Cosine Law ZX=sqr(XY^2+YZ^2-2•XY•YZ•cos135) =sqr(9+25+30 (-0.707))= 7.43 km ≈7 km.

13 years ago

Linear momentum p=mv=0.175•1.65=0.289 kg•m/s Angular momentum L=I•ω=(mr^2/2) •ω=(0.175•(0.12)^2/2) •61.5=77.5 kg•m^2/s

13 years ago

torque= force (N) x radius (m)

13 years ago

For decelerated motion s= vt-at^2/2. a=2(vt-s)/t^2=2(37•3.5-6)/3.5^2=20.16 m/s^2

13 years ago

E=kq/r^2 q=E•r^2/k=20•0.16/9•10^9=0.36•10^-9 C= 0.36 nC

13 years ago

F12=k•q1•q2/(r12)^2=1.08•10^-5 N (to the right) F13= k•q1•q3/(r23)^2=2.16•10^-5 N (upwards) F=sqroot(F12^2+F13^2)=2.4•10^-5 N Direction of F respectively x-axis: tan α=F13/F12= 2, α = 63.4 degr

13 years ago

An angular velocity is ω =2πn= 5.5•2π/60= 0.58 rad/s. Linear speed v= ωR=0.58•4.25=2.45 m/s, Radial acceleration a = ω^2•R=(0.58)^2•4.25=1.43 m/s^2 Since ω = εt , an angular acceleration ε = ω/t=0.58/26=2.23•10^-2 rad/s^2, Tangential acceleration a = ε•R=...

13 years ago

Newton’s 2 Law for rotation: M=I• ε, angular acceleration is ε = M/I=170/0.53=320.8 rad/s^2 Final angular velocity (if initial velocity is zero) is ω = εt = 320.8•0.15= 48.1 rad/s. v= ωR = 48.1•0.76= 36.6 m/s

13 years ago

PE=kA^2/2=240•(0.12)^2/2=1.728 J.

13 years ago

The moment of inertia of weather vane with piece of clay is I = I(vane) +mR^2 = 0.115+44.5•10^-3•(0.105)^2= = 1.2•10^-2 kg • m2. The torque due to the clay hitting is M=F•R F•t=Δp=m•v, therefore F=m•v/t. Then M=F•R=m•v•R/t. From Newton’s 2 Law for rotatio...

13 years ago

torque = force•arm of the force = =1.89•10^4•39.3=7.43•10^5 N•m

13 years ago

KE=PE=mgh=7.2x9.8x1.2=84.7 J

13 years ago