Total # Posts: 3,217
A 100-g chunk of 72 ∘C iron is dropped into a cavity in a very large block of ice at 0∘C. What is the mass of ice that melts. (The specific heat capacity of iron is 0.11 cal/g⋅∘C.).
July 4, 2016
Many people mistakenly believe that the astronauts who orbit Earth are "above gravity." Earth's mass is 6×1024kg, and its radius is 6.38×106m (6380 km). Use the inverse-square law to find a height above Earth's surface at that the force of gravity...
June 21, 2016
A penny on its side moving at speed v slides off the horizontal surface of a table a vertical distance y from the floor. If the speed is 3.1 m/s and the coffee table is 0.30 m tall, find the distance the coin lands from the base of the table. (Use g=9.8m/s2.).
June 21, 2016
A base of a solid is the region bounded by y=e^-x, the x axis, the y axis, and the line x=2. Each cross section perpendicular to the x-axis is a square Find the volume of the solid
June 2, 2016
If rectangle ABCD has vertices A(6, 2), B(2, 2), and C(0, 6), explain how to find the coordinate for the fourth vertex. Then describe how to verify that the angles of ABCD are right angles.
May 24, 2016
as the permeability of a material is the ratio of the magnetic field strength and the magnetic flux, could the permeability of the material be multiplied by the magnetic field strength in order to calculate the flux?
May 22, 2016
7 g bullet is ﬁred into a 124 g block that is initially at rest at the edge of a frictionless table of height 1.3 m. The bullet remains in the block, and after impact the block lands 2.2 m from the bottom of the table. Find the initial speed of the bullet. The ...
May 7, 2016
A typical red blood cell subtends an angle of only 1.7×10−5 rad when viewed at a person's near-point distance of 25 cm. Suppose a red blood cell is examined with a compound microscope in which the objective and eyepiece are separated by a distance of 13.0 cm . ...
April 22, 2016
Find the minimum aperture diameter of a camera that can resolve detail on the ground the size of a person (1.5 m ) from an SR-71 Blackbird airplane flying at an altitude of 26 km . (Assume light with a wavelength of 470 nm .) I got 570 mm which is wrong
April 21, 2016
Emily fills a container with 6cubes. Each cube has an edge length of 3cm. The container is in the shape of a right rectangular prism. What is the volume of the container in cubic cm
April 18, 2016
check my answers please
1.)order the group of quadratic fractions from widest to narrowest graph. y=3x^2;y=5x^2;y=7x^2 a.)y=3x^2;y=5x^2;y=7x^2 b.)y=7x^2;y=5x^2;y=3x^2 c.)y=3x^2;y=7x^2;y=5x^2*** d.)y=2x^2;y=7x^2;y=3x^2 2.)the area of a play ground is 234yd^2. the width of the playground is 5 yard ...
April 12, 2016
Math Check my Answers please ?
1.)if an object is dropped from a height of 144 ft the function h(t)=-16t^2+144 gives the height of the object after t seconds. when will the object hit the ground? a.)1.5 seconds b.)3 seconds *** c.) 6 seconds d.)9 seconds 2.) the area of a play ground is 64 square yards. the...
April 12, 2016
Please help ! 1.)a catapult launches a boulder with an upward velocity of 122 feet per second. the height of the boulder, h, in feet after t seconds is givin by the function h(t)=-16t^2+122t+10. what is the boulders maximum height ? and how long does it take the boulder to ...
April 11, 2016
A survey revealed that 44% of movie goers will eat some amount of popcorn during a movie. If the next 17 movie goers are asked if they will eat popcorn during the next movie they attend, what is the probability that at least 8 will say they will eat popcorn during the next ...
March 19, 2016
The quotient for 20÷1/4 is 5. It wants to know which expression has the same quotient as 20÷1/4. A.1/2÷40 B.1/4÷20 C.15÷1/5 D.6÷1"10 None of these have the quotient of 5. So what are we doing wrong cause none have the choice of ...
March 17, 2016
In To Kill A MockingBird book by Harper Lee. What is the Boo Radley game? Who plays it and how do the different characters feel about it? In your response refer closely to the text to build a convincing argument.
March 14, 2016
Physics (Inside the atom)
A sample of radioactive isotope I is to be used for medical diagnosis of the kidneys. The isotope has a half-life of 8.0 days, and the sample is required to have an activity of 8 x 10^5 per second at the time it is given to the patient. Calculate the mass of the I-131 present ...
March 10, 2016
A family is building a circular fountain in the backyard the yard is rectangular and measures 6x by 7x and the fountain is going to be circular with a radius of 2x once the fountain is built what will be the area of the remaining yard?
March 9, 2016
4. Suppose that an excess of propane, C3H8 , burns in 320 g of oxygen, How many moles of water will be formed? C3H8 + 5 O2 --> 3 CO2 + 4 H2O (1 point) 6.02 E 23 moles 1600 moles 4.0 moles 8.0 moles
February 16, 2016
Given that A= 4.00i(hat)+ 10.0j(hat)and B = 3i(hat)-5.00j(hat), find the magnitude and directions(i.e., angle with respect to the +x axis) of C= A+B magnitude = 8.6 I cant find out how to find the angle
February 10, 2016
There are 5 chairs in a row, and three people. In how many ways c an you place the people on the chairs? (each person must occupy exactly one chair, so that two chairs will remain free).
February 4, 2016
The salary scale in three school districts are as follows, for a teacher with a masters degree: District P: $30,000 plus $1500 for each year of experience District Q: $30,000 plus $1750 for each year of experience District R: $28,000 plus $1750 for each year of ...
February 1, 2016
In which step is the error? Step 1: Let x = 1 and y = 1. Step 2: By substitution xy = y^2. Step 3: Multiplying both sides by -1, -xy= -y^2. Step 4: Adding x^2 to both sides, x^2-xy=x^2-y^2. Step 5: Factoring, x(x-y)=(x+y)(x-y). Step 6: Dividing both sides by x-y, x=x+y. Step 7...
February 1, 2016
A blue car pulls away from a red stop-light just after it has turned green with a constant acceleration of 0.2 m/s2. A green car arrives at the position of the stop-light 7.5 s after the light had turned green. What is the slowest constant speed which the green car can ...
January 31, 2016
The ramp shown below is used to move crates of fruit to loading docks of different heights. When the horizontal distance AB is 12 meters, the height of the loading dock, BC, is 4 meters. What is the height of the loading dock DE? A. 12m B. 8m C. 9m D. 15m My answer is 9 is ...
January 29, 2016
When you turn on a battery powered flashlight you transform... 1) heat into light chemical energy 2) chemical energy into electrical energy and light 3)heat into chemical energy and light 4) electrical energy and light energy into chemical energy
January 28, 2016
Which of the following state program areas consumes the largest part of the executive budget? (1 point) human services education *** natural resources transportation 2. Which state department is responsible for mental health-related issues and welfare? (1 point) human services...
January 22, 2016
Would there be any effect on the amount of precipitate in the experiment if tap water containing calcium ions is used instead of deionized water to dissolve the reactants. Assume that Na2CO3 is present in the excess.
January 18, 2016
check my english pleaseee
1.)the storm *remains* a threat to the costal village a.)action verb b.)linking verb** c.)direct object d.)indirect object. 2.)which of these is a direct characterization of ted from " my brothers keeper " a.)im your kids brother five years younger than you are and ...
January 8, 2016
3(y+2) for y = 3 a. 21 b. 18 c. 15 d. 12 simplify 3+6y-2y+4 a. 4y+7 b. 8y+7 c. 6x-6 d. 9x-4 simplify 2(3x-2)+3x a. 9x-6 b. 6x-4 c. 6x-6 d. 9x-4 which number is the solution of x/4=-5? a. 20 b. 1.25 c. -1.25 d. -20 what is the solution to 12x=240? a. 20 b. 1.25 c. -1.25 d. -20 ...
January 4, 2016
Imagine a landing craft approaching the surface of the moon of a distant planet. If the engine provides an upward force (thrust) of 2890 N, the craft descends at constant speed; if the engine provides only 2200 N, the craft accelerates downward at 0.36 m/s2.
January 2, 2016
To pass a course with a C grade, a student must have an average of 70 or greater. A students grades on three tests are 63, 76, 67. Find what score the student must get on the next test to get a C average or better
December 14, 2015
Two ocean beaches are being affected by erosion. The table shows the width, in feet, of each beach at high tide measured where 1995 is represented by year 0. Western beach width Dunes beach Year number (in feet) width (in feet) 0 100 20 5 90 45 10 80 70 11 78 75 12 76 80 15 70...
December 10, 2015
A. they would not make any changes in their behavior. B. They would demand more public goods and services. C. They would stop voting in elections. D. They would not re-elect the leaders. i think A.
November 24, 2015
Social studies (check please!)
Which of these goods or services is paid for with federal taxes 1 community roads 2 military bases 3 public universities 3 police protection 3 Is correct
November 24, 2015
XYZ Gaming Inc. Wants to invest in some new goods to raise it's overall productivity. Which of these would be the best choice? Bigger desks for workers -- Faster Internet Service -- (Correct!) -- A new lunchroom -- Health training for employees --
November 24, 2015
a bakery sells bagels for $0.85 each an muffins for $1.10 each the bakery hopes to earn $400 each day from these sales. Write an equation that represents the total amount the bakery would like to earn selling bagels and muffins each day. (sorry I have no idea how to do this...
November 19, 2015
A 48-kg box is being pushed a distance of 7.5 m across the floor by a force Upper POverscript right-arrow EndScripts whose magnitude is 185 N. The force Upper POverscript right-arrow EndScripts is parallel to the displacement of the box. The coefficient of ...
November 18, 2015
Starting with an initial speed of 3.86 m/s at a height of 0.480 m, a 1.78-kg ball swings downward and strikes a 4.75-kg ball that is at rest, as the drawing shows. (a) Using the principle of conservation of mechanical energy, find the speed of the 1.78-kg ball just before ...
November 17, 2015
Batteries are made of two metals with different electron affinities. What does the phrase electron affinity mean and how does this affinity affect the voltage of the battery
November 12, 2015
Two newly discovered planets follow circular orbits around a star in a distant part of the galaxy. The orbital speeds of the planets are determined to be 36.0 km/s and 50.6 km/s. The slower planet's orbital period is 7.78 years. (a) What is the mass of the star? (b) What ...
November 8, 2015
A "swing" ride at a carnival consists of chairs that are swung in a circle by 11.5 m cables attached to a vertical rotating pole, as the drawing shows. Suppose the total mass of a chair and its occupant is 204 kg. (a) Determine the tension in the cable attached to ...
November 8, 2015
Please check my answers. Which of the following sentences is punctuated correctly ? On January 1, 2000, many people thought that the new millennium would bring the end of the world,but it didn't ******** On January 1 2000, many people thought that the new millennium would ...
October 28, 2015
A person is trying to judge whether a picture (mass = 2.37 kg) is properly positioned by temporarily pressing it against a wall. The pressing force is perpendicular to the wall. The coefficient of static friction between the picture and the wall is 0.760. What is the minimum ...
October 22, 2015