Friday

August 1, 2014

August 1, 2014

Total # Posts: 615

**Physics**

A stack of books rests on a level perfectly smooth surface. A force F acts on the stack and it acclerated at 3m/s^2. A 1kg book is added to the stack. The same force is applied and now the stack accelerates at 2m/s^2. What was the mass of the original stack? I think i would us...

**Physics**

A stone is thrown straight up. At the top of the path, the net force acting on it is (ignore air resistance) a) greater than its weight b) greater than zero, but less than its weight c) instantaneously equal to zero d) equal to its weight At the very top of the path wouldn'...

**Physics**

A constant net force acts on an object. Describe the motion of the object. a) constant acceleration b) constant speed c) constant velocity d) increasing acceleration I believe the answer would be a) constant acceleration. Given F=ma. Is this correct?

**Chemistry**

Unfortunately I was hit by the sweep of illnesses going around due to changing whether and missed school today. Thus I missed the notes in Chemistry leaving me completely confuzzled about tonights homework on Dimmensional analysis or Unit Factoring. I called a friend but she i...

**college class**

Consider the choices of Native Americans who decide to stay on their tribe's native land or reservation, and those who choose to relocate to a city. If you were presented with this decision, which would you choose and why? Please be sure to fully explain your answer in a s...

**Physics**

A projectile is launched from ground level with an inital velocity of 50 m/s at an angel of 60 degreess aove the horizontal. Use g=10m/s. What is the max height reached by the projectile? I used change in y=voyt +1/2at^2 =50(2.4) + 1/2(=10) (2.5)^2 =125-31.25 =93.75m I was jus...

**Physics**

When a football in a field goal attemp reaches its max height how does its speed compare to its inital speed? a)it's zero b) it is less than its inital speed c)it is equal to its inital speed d)it is greater than its inital speed since at the max height v=0 isn't the a...

**Physics**

a ball thrown horizontally from a point 40m above the ground,strikes the ground after traveling a distance of 9m. with what speed was it thrown? use g=10m/s^2 first i need to find the time so I used y=y_0 +v_0t +1/2at^2 -40=-1/2(10)t^2 t=8s then x=x_o+vt 9=v(8) v=1.125m/s Is t...

**Physics**

A projectile is shot horizontally at 30m/s from the roof of a building 100m tall. Use g=10m/s^2. Choose + vertical direction to be pwards. a) determine the time necessary fot the projectile to reach the ground below b) determine the horizontal distance from the base of teh bui...

**Physics**

A jumper in the long-jump goes into the jump with a speed of 10m/s at an angle of 30 degrees above the horizontal. Use g=10m/s. a) how long in the air is the jumper before returning to the Earth? b) How far does the jumper jump? for a) I got .001s as the answer which logically...

**Physics**

A plane flying horizontally at a speed of 50m/s and at an elevation of 160m drops a package. two seconds later it drops a second package. How far apart will the two packages land on the ground? a)100m b)162m c)177m d)283m i think the answer is a) I got 150m for the first packa...

**Physics**

When a football in a field goal attemp reaches its max height how does its speed compare to its inital speed? a)it's zero b) it is less than its inital speed c)it is equal to its inital speed d)it is greater than its inital speed since at the max height v=0 isn't the a...

**Physics**

A jumper in the long-jump goes into the jump with a speed of 10m/s at an angle of 30 degrees above the horizontal. Use g=10m/s. a) how long in the air is the jumper before returning to the Earth? b) How far does the jumper jump? for a) I got .001s as the answer which logically...

**Physics**

A projectile is shot horizontally at 30m/s from the roof of a building 100m tall. Use g=10m/s^2. Choose + vertical direction to be pwards. a) determine the time necessary fot the projectile to reach the ground below b) determine the horizontal distance from the base of teh bui...

**Physics**

A projectile is shot horizontally at 30m/s from the roof of a building 100m tall. Use g=10m/s^2. Choose + vertical direction to be pwards. a) determine the time necessary fot the projectile to reach the ground below b) determine the horizontal distance from the base of teh bui...

**Physics**

"from zero to sixty in 8 seconds" is a description of: a) average speed b) instantaneous speed c)average acceleration d) instantaneous acceleration I know for sure that a) and c) aren't the right answers since average is over a long time period or the whole trip....

**Physics**

Suppose that a car traveling to the West (-x direction) begins to slow down as it approaches a traffic light. make a statement concerning its acceleration. a) the car is decelerating and its acceleration is positive b)the car is decelerating and its acceleration is negative c)...

**Physics**

A car starts from rest and accelerates at 5m/s^2 for 4s, then maintains that velocity for 3 seconds and then decelerates to a rate of 2m/s^2 for 3 seconds. How far does the car travel? I would have to add the total distance throughout the trip. And to find the distance I would...

**Physics**

On a postition versus time graph to find the acceleration you would simply find the area under the graph right? and how would you figure out whether acceleration is increasing, decreasing, constant of unknown from a graph? My guess is that the accereration is constant throughout.

**Physics**

A small mailbag is releassed from a helicopter that is ascending steadily at 5m/s. After 2s. a) what is the speed of the mailbag? b) how far is it below the helicopter? a) would I use v=v_0 +at v=5m/s + 9.8m/s^2(2s) v=24.6 m/s is this the correct speed of the mailbag? For b) i...

**Physics**

Killer whales at Sea Worl routinely jump 8 m above the water. What is their speed as they leave the water to achieve this? I know that h=8m v=? Would I use h=h_0 + v_0t = 1/2 at^2 but the problem would be that I also don't know the time. I am confused about which equation ...

**Physics**

Three vectors, each have a magnitude of 30 units, have their tails at the same oint and are directed 120 degrees from each other. Make a statement concerning the sum of these three vectors. a) the sum vector is 0 b) the sum vector is greater thatn 30 c) the sum vector is equal...

**Physics**

The sum of 2 vectors is the smallest when the angle between them is : a) 0 b) 45 c) 90 d) 180 d) i believe is the correct answer but i'm not sure exactly. Thanks in advance for your help.

**Physics**

Which of the following is an accurate statement? a) a vector cannot have zero magnitude if one of its components is not zero b) the magnitude of a vector can be less than the magnitude of one of its componenets c) if the magnitude of vector A is less than the magnitude of vect...

**inb-check this please**

thank you

**inb-check this please**

Developed country partners in countertrade contracts have had problems with quality and timely delivery of goods from the developing country partners. How are they trying to deal with those problems? 1999, 12 of the 15 European Union (EU) member-countries agreed to begin a tra...

**inb**

Developed country partners in countertrade contracts have had problems with quality and timely delivery of goods from the developing country partners. How are they trying to deal with those problems?

**Physics**

A car starts from rest and undergoes uniform acceleration. During the first second it travels 6 m. a) what is the car's acceleration? b) How far will the car travel during the third second? For a) I used v= v_0 +at 6=0 a*1 so a= 6m/s^2 For b) I used d=vt d=6(3) = 18 m Did ...

**Physics**

A car starts from rest and accelerates at 5 m/s^2 for 4 s, then maintains that velocity for 3 seconds, then decelerates at the rate of 2m/s^2 for 3 seconds. a) what is the final speed of the car? b) how far does the car travel? a) v = v_0 +at = 0+5(4)= 20m/s =0+5(3)= 15m/s =0+...

**Physics**

You are driving home on a weekend from school at 65mph for 130 miles. It then starts to snow and you slow to 45 mph. You arrive home after driving 4 hours. How far is your hometown from school? First I found the time with d/v=t so 130/65= 2 hours I used d= d_0 +vt =130 +45(6) ...

**Physics**

A car with good tires on a dry road can decelerate at about 5 m/s^2 when breaking. Suppose a car is initially traveling at 65 mph. What is the stopping distance?(give answer in meters and in feet) I changed 65mph into 29.05m/s. so I would use d-d_0 = (v^2 -v_0^2)/2a and when I...

**Physics**

You are driving home on a weekend from school at 65mph for 130 miles. It then starts to snow and you slow to 45 mph. You arrive home after driving 4 hours. How far is your hometown from school? First I found the time with d/v=t so 130/65= 2 hours Then I used d= (v-v_0)/(t-t_0)...

**Physics**

A car starts from rest and accelerates at 5 m/s^2 for 4 s, then maintains that velocity for 3 seconds, then decelerates at the rate of 2m/s^2 for 3 seconds. a) what is the final speed of the car? b) how far does the car travel? a) v = v_0 +at =0+2(3)= 6m/s Would I use the part...

**Physics**

A car starts from rest and undergoes uniform acceleration. During the first second it travels 6 m. a) what is the car's acceleration? b) How far will the car travel during the third second? For a) I used v= v_0 +at 6=0 a*1 so a= 6m/s^2 For b) I used d=d_0 +v_0t + 1/2 at^2 ...

**Physics**

If you are driving at 65mph along a straight road and you look to the side for 2 seconds, how far do you travel during this inattentive period? (Give the answer in meters and in feet) Would i use d= d_0 + vt to solve this problem or would I use another equation? When i used th...

**Physics**

Suppose that an object travels from one point in space to another. Make a comparison between the displacement and the distance traveled. a) the displacement is either greater than or equal to the distance traveled b)the displacement is always equal to the distance traveled. c)...

**Physics**

When is the average velocity of an object equal to the instantaneous velocity? a) always b)never c) only when velocity is constant d)only when velocity is increasing at a constant rate c) would be the answer since you could cross out a). I do know that instantaneous velocity i...

**Physics**

a car manufacture advertise that a car goes "from zero to sixty in 8 seconds" is a description of: a) average speed b) instantaneous speed c) average velocity d) instantaneous acceleration a) and b) are incorrect since it's a change in velocity, whcih means it...

**science**

Object A and B both start at rest. They both accelerate at the same rate. However , object A accelerates for twice teh time as object B. What is the distance traveled by object A compared to that of object B? a) the same distance B) twice as far c) three times as far d) four t...

**science**

a car manufacture advertise that a car goes "from zero to sixty in 8 seconds" is a description of: a) average speed b) instantaneous speed c) average velocity d) instantaneous acceleration a) and b) are incorrect since it's a change in velocity, whcih means it...

**science**

When is the average velocity of an object equal to the instantaneous velocity? a) always b)never c) only when velocity is constant d)only when velocity is increasing at a constant rate c) would be the answer since you could cross out a). I do know that instantaneous velocity i...

**science**

Suppose that an object travels from one point in space to another. Make a comparison between the displacement and the distance traveled. a) the displacement is either greater than or equal to the distance traveled b)the displacement is always equal to the distance traveled. c)...

**science**

An average human heart rate is 70 beats per minute. How many times it beats over 70 year lifetime? use scientific notation. 365 = the number of days in a year 70 years /1 * 365 days / year = 25,550 25,550/1 * 24 hours/ day = 613,200 613,200/1 * 60 minutes/ hour =36,792,000 70 ...

**Precalculus**

Write the statement using absolute value notaion: The distance between x and 1 is 7. I got the answer as the absolute value of x, plus 7 equals 1 Is that correct?

**Conversion**

How many cubic millimeters are there in one square centimeter? I know that in one square centimeter there is 100 millimeters squared. So this is what I did: x^3 = 100^2 so x=100 is this correct?

**Algebra**

I think that the goal is to get rid of the 5th root in this case. I know that I have to make whatever is under or in the root -in this case the number is X equal some number to the fifth power. I am supposed to use the rule a^(m/n)= n (the n-root) (don't know how to type i...

**Algebra**

Please read and then help me! (x^(-3/5)) ----------- divide x ^ (1/5) I know the problem then needs to look like this: (x^(-3/5))(x^(-1/5)) (multiply the two above) Then it needs to look like this: (I can't write it though, so I'll tell you) The 5th root out of (x^(-3)...

**Rational Expressions Algebra**

Electronics The electrical resistance (r) of a cable varies directly (y=kx) as its length (l) and inversely (y= k/x) as the square of its diaeter (d). If a cable 16,000 ft long and 1/4 in. in diameter has a resistance of 3.2 ohms, what is the resistance of a cable that is 8000...

**Algebra**

Simplify [(1)-(1/x+2)] / [(1)- (3/x+4)] I know I need to find the LMC here, and the answer is (x+4)/(x+2) but I do not know how to get to the answer and how to use the LMC. I need help! You need to use more parentheses to distiguish (1/x)+ 2 from 1/(x+2), and (3/x)+4 from 3/(x...

**algebra**

Solve Q=(n-s)/n for n To get you started, multiply both sides by n and go from there. Post your work if you get stuck AND tell us what you don't understand about the next step.

**Algebra**

(3x+4)/(3x-4)+(3x-4)/(3x+4) --------------------------- Divide top by bottom (3x-4)/(3x+4)-(3x+4)/(3x-4) Very Big Problem and help would be greatly appreciated not that tough once you notice that your question has the pattern (a/b + b/a)÷(b/a - a/b) where a = 3x+4 and b...

**math**

describe an application for the use of ratios or portions. And describe how an application problem could be useful in daily life? Lok at the post directly below yours. I think it will serve as an example.

**International business**

I need help with finding a potential market and product to get my export operations started. I need a 15to20 PowerPoint presentation with detailed speakers notes that analyze a potential international business opportunity. Thank you for using the Jiskha Homework Help Forum. Ho...

**Chemistry**

The solubility of KCLO3 at 25 degree celcius is 10.9 per 100.g of h20. question: If 15 g are addded to 100 g of water at 25 degree celcius with stirring, how much of KCLO3 will dissolve? Is the solution saturated, unsaturated, or supersaturated? please help me with this quesit...

**calculus**

First I would find the first derivative which is the slope and then would I plug in the given value into the original equation to find y and then use y-y_1=m(x-x_1)? Find the euation of the tangent line at the given value a) y=ln abs(x+4) x = -3 b) y= (x^2 +5)/(x+1) x=1 a) I f...

**Calc**

intergral of (x^3 -4x + 3)/(2x) dx would this be ln abs(x^3-4x+3) + C? I don't really understand how to solve this problem. d/dx (tan (x^2)) sec^2(x^2)(2x) would this be the correct answer to find the derivative of tan (x^2)? no, because if you differentiate your answer yo...

**Calc**

Find the derivative of a) y=cos (x/2) b) yx-3x^2 +6 = y^4 + x a) -sin (x/2)(2+x)/2^2 -sin(x/2)(x/2) b) x dy/dx + y - 6x = 4y^3 dy/dx + 3x^2 dy/dx (x -4 y^3) = 3x^2 -y +6x dy/dx = (3x^2 -y +6x)/(x -4 y^3) I used inplicit differation for part b are these correct? Thanks for your...

**algebra**

i am supose to graph this using three points on a graph how am i suppose to find three points for this problem x<=2 What about x=2, y = anything; x=1, y= anything; and x=-4, y= anything. I would write as as x+y<=2 2+y<=2 then solve for y to get my points

**algebra word problem**

A small company produces both dollhouses and sets of doll furniture. The dollhouses take 3 hours of labor to produce, and the furniture sets take 8 hours. The labor available is limited to 400 hours per week, and the total production capacity is 100 items per week. Existing or...

**math word problems**

The sum of two numbers is 69. The second is 9 more than 4 times the first. What are the two numbers? would the equation i have be right 4x+y+9=69 4*15+0+9=69 60+9=69 couldn't it also be: 4x+y+9=69 4*14+4+9=69?

**math word problems**

The sum of two numbers is 69. The second is 9 more than 4 times the first. What are the two numbers? would the equation i have be right 4x+y+9=69 4*15+0+9=69 60+9=69 No. Let the two numbers be x and y, with x the smaller number. x + y = 69 y = 4x + 9 5x + 9 = 69 x = 12 Use any...

**algebra**

Solve the system by graphing. x + y = 4 –x + y = 2 confused where do i start do i need to solve for x and find points I'll bet that after doing a few like this you would be able to do this one in your head. just add then up. The x's will cancel and you will have 2...

**ALGEBRA**

Find all positive values for k for which each of the following can be factored. I have 2 problems i think i got the one right but not sure the second one i have no idea where to even start 2x^3+16x^2-40x=2x(x^2+8x-20) (x-2)(x+10)=8x this one i am stumped can some one explain t...

**math**

For the universal set U= {0,1,2,3,4,5,6,7} And the sets A={1,5}, B={1,2,3,4} And C= {4, 6} lists the elements in the following Sets. a. A ¢¯ B b. A U Bf c. A ¢¯(B U C) d. C ¢¯ (B ¢¯ A)f U means: state ...

**math**

I need help with slopes and lines. Determine the slope of each line a line through points (-1, 2) and (2, -7) Slope of a line through two points (x1, y1) and (x2, y2) is (y2 - y1)/(x2 - x1). So substituting the given points we have (-7 - 2)/(2 - (-1)) i.e -9/3 = 3 Oops. it sho...

**english**

can someone help me correct it Is consumerism taking over mens lives?

**Physics**

A force F is exerted by a broom handle on the head of the broom, which is of mass m. The handle is at angle theda to the horizontal. (where it's tilted towards the left at about 30 degrees to the horizonal). The work is: a)fdsin theda b)fdcos theda This would be b) right? ...

**Physics**

When a block slides a certain distance down an incline the work done by gravity is 300 J. What is the work done by gravity if this block slides the same distance up the incline? a) 300 J b) zero c) -300 J d) It cannot be determined without knowing the distance the block travel...

**Physics**

A ball is tossed straight up from the surface of a small spherical asteroid with no atmosphere. The ball goes to a height ewual to the asteroid's radius and then falls straight down towardd the surface of the asteroid. What forces if any act on the ball while it is on the ...

**Physics**

F=kx k=100 x=.03 F=100*.03=3N (directed towards center b/c Centrip. force always does that)

**Physics**

A spring has a force constant of 100N/m and an unstretched lenght of .07 m. One end is attached to a post taht is free to rotate in the center of a smooth table. The other end is attatched to a 1 kg disc moving in uniform circular motion on the table, which stretches the sprin...

**Physics**

A wheel with rotational inertia I is mounted on a fixed, fricitonless axle. The angular speed w of the wheel is inccreased from zero to w_f in a time interval T. 1: What is the average net torque on the wheel during the time interval, T? a) w_f/T b)w_f/T^2 c) Iw_f^2/T d)Iw_f/T...

**Physics**

When a block slides a certain distance down an incline the work done by gravity is 300 J. What is the work done by gravity if this block slides the same distance up the incline? a) 300 J b) zero c) -300 J d) It cannot be determined without knowing the distance the block travel...

**Physics**

To streatch a certain nonlinear spring by an amount 2x requires a force F given by F=40x-6x^2 where F is in newtons and x is in meters. What is the change in potential energy when the spring is stretched 2 meters from its equilibrium position? a)16 J b)28 J c)56 J d)64 J e)80 ...

**Physics**

A target lies flat on the ground 3m from the side of a building which is 10m tall. A student rolls a ball off the horicontal roof of the building in the direction of the target. Air resistance is negligible. Te horizonal speed with which the ball must leave the roof if it is t...

**Physics**

The velocity of a projectile at launch has a horizontal component v_h and a vertical component V_V. Air resistence is negligible. When the projectile is at the hightest point of its trajectory, which of the following show the vertical and horizontal components of its velocity ...

**Physics**

An ideal massless spring is fixed to the wall at one end. A block of mass M attached to the other end of the spring oscillates with amplitude A on a frictionless, horizontal surface. The maximum speed of the block is V_m. The force constant of the spring is a)Mg/A b)MgV_m/2A c...

**Physics**

A spring has a force constant of 100N/m and an unstretched lenght of .07 m. One end is attached to a post taht is free to rotate in the center of a smooth table. The other end is attatched to a 1 kg disc moving in uniform circular motion on the table, which stretches the sprin...

**Physics**

A ball is tossed straight up from the surface of a small spherical asteroid with no atmosphere. The ball goes to a height ewual to the asteroid's radius and then falls straight down towardd the surface of the asteroid. What forces if any act on the ball while it is on the ...

**Physics**

The position of a toy locomotive mobing on a straight track along the x-axis is given the equation x=t^3-6t^2 +9t where x is in metters and t is in seconds. The net force on the locomotive is equal to zero when t is eqaul to a) zero b)2 s c)3 s d)4s e)5s Would the answer be b)...

**accounting**

if a bond sells at 102.5, what does that mean?

**Physics**

After a completely inelastic collision two objects of the same mass and the same initial speed are found to move away together at 1/2 thier initial speed. Find the angle bewteen the initial velocitie of the objects? Can you please show me the step to solve this problem? I am r...

**Physics**

A 50g mass (M1) will be attached to the trolley M2) and will cause it to accelerate a distance of between .5 to .6m. You also catch the trolley immediately after it has passed through the photogate. The time for the trip will be noted and recorded. The trolley is on a track. T...

**Of mice and men**

Would you say Steinbeck uses indirect or direct characterization of the characters? I think it's direct. For example he says, "The first man was small and quick, dark of face, with restless eyes and sharp features," (Steinbeck 2). I think you're right. That&#...

**math help**

Kim was charged $150.00 interest for 1 month on a $10,000 credit card balance. What was the monthly interest rate?

**Physics**

Trolley B will be at rest and trolley A will be given a push such that it collides with B, and they both move as one mass after the collision. As soon as the blocker of the picket fence on trolley A passes through the eye of the first photogate, trolley A must collide with tro...

**Physics**

A railroad flatcar of weight W can roll without friction along astraight horizontal track. Initially, a man of weight w is standing on the car, which is moving to the right with speed v_0. What is the change in velocity of the car if the man runs to the left so that his speed ...

**area/length/volume**

the volume of the substance may Have a different weight. Such as a cup full of cottoncandy and a cupfull of rocks

**Physics**

A rocket whish is in deep space and initially at rest relative to an inertial reference frame, has a mass of 2.55 X 10^5 kg of which 1.81 X10^5 kg is fuel. The rocket engine is then fired for 250 s during which feul is consumed at the rate of 480 kg/s. The speed of the exhaust...

**Physics**

A 6090kg space probe mobing nose-first toward Jupiter at 105m/s relative to the Sun, fires its rocket engine ejecting 80 kg of exhaust at a speed of 253 m/s relative to the space probe. What is the final velocity of the probe? I should have gotten 108m/s Can yoou show me the c...

**math check please**

Find the median of the following set of numbers 45,21,54,22,65,61 Answer 49 1/2 2. find the mean and the median of the set of grades 95,75,76,86,96,71,68,81,95,76,69,82,93,88,94 Answer mean 83 median 82 3. find the mode of the following numbers 11,10,6,11,12 Answer 11 4. Find ...

**Physics... Please help me! I REALLY need help.**

A .30kg softball had a velocity of 15m/s at an angle of 35 degrees below the horizontal just before making contact with the bat. What is the magnitude of the change in momentum of the ball while it is in contact with the bat if the ball leaves the bat with a velocity of a)20m/...

**Speech**

A concluding strategy which helps to promote unity within a speech is a)a summary of main points b)a rhetorical question c)a refernce to the introduction D)a statistic The conclusion is supposed to tie the discoveries to the proposition in the introduction. So, I am suggesting...

**Physics**

A .30kg softball had a velocity of 15m/s at an angle of 35 degrees below the horizontal just before making contact with the bat. What is the magnitude of the change in momentum of the ball while it is in contact with the bat if the ball leaves the bat with a velocity of a)20m/...

**Science**

Does increasing the frequency of a wave also increase its wavelength? If not, how are these quantities related? high frequency. low wavelength That answer may be confusing. A high frequency has a short wavelength; i.e., 14 MHz is about 40 meters. 28 MHz is abouat 10 meters. 50...

**math help please**

(-3)^3-(-8)(-2)= -3 to the 3 power is -27 subtract -27 - -8 = -19 multiply by -2 =38 is this right please help (-3)^3-(-8)(-2) Use BODMAS rule So the answer is (-3)^3-16 ==>-27-16 =-43

**math check please**

region Population land area 1000mi^2 Asia 4,028,000,000 17,400 North America 305,000,000 9,400 1. Compare the populations per square mile in asia to the population per square mile in north america A: Asia 231.49mi^2 North America 32.45mi.^2 could some one please let me know if...

**Science**

A golf ball and a ping-pong ball are dropped in a vacuum chamber. When they have fallen halfway down, they have the same... A.speed B.potential energy C.kinetic energy D.Rest Energy my thought is that its c, kinetic energy...but i'm not 100% sure

**maths-- compound interest**

do you times the nt by the equation results to get the answer

**maths-- compound interest**

if investing 50,000 over 20 yrs at 3%apr with compouind interest figures semi-annually .figure using equation f(t)=p(1+r/n)nt

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