# Posts by Jean

Total # Posts: 501

Chemistry
An unknown element Q has two known isotopes: 60Q and 63Q. If the average atomic mass is 62.0 amu, what are the relative percentages of the isotopes?

statistics
Car seat belts are tested for strength, and it is found the results are normally distributed with a mean of 2400 lb and a standard deviation of 400 lb. Using the 68-95-99.7 rule, find the percentage of scores between 1600 lb and 3200 lb.

physics
the rate at which radiant energy from the sun reaches the earth's upper atmosphere is about 1.50kW/m2. the distance from the earth to the sun is 1.50*10^11m, and the radius of the sun is 6.96 * 10^8m. if the sun radiates as an ideal black body (e=1), what is the ...

Math
In a survey of students about favorite sports the results include 23 who like tennis 24 like football 7 like tennis and football 20 like football and baseball 5 like all three sports 9 like no sports. How many students like only tennis and football? How many like only tennis ...

chemistry
Consider the equilibrium reaction CO(g)+H2O(g)⇋CO2(g)+H2(g) Determine how each change in the left-hand column will stress the system and in which direction the equilibrium reaction will shift in response.

math
39

physics
How much effort force would be needed to roll a barrel with a resistance force of 100N up an inclined plane with a height of 2m and an inclined plane of 8m?

Statistics
what is the standard deviation for 57,61,57,57,58,57,61

precalc
Find the standard form equation for each ellipse described. 1) Major vertices at (0, 3) and (0, -3), minor vertices at (2, 0) and (-2, 0) 2) Major vertices at (7, 0) and (-7, 0), foci at (5, 0) and (-5, 0) 3) Minor vertices at (-2, -3) and (-2, -11), foci at (1, -7) and (-5, -7)

statistics
16/2704 =1/169 or 0.0059 144/2704 = 9/169 or 0.0533

Intro to Ecology
Global estimates of denitrification in terrestrial ecosystems vary widely but are of the order 200*102 g/yr, and more than half of that total occurs in wetland ecosystems. If restoration results in an increase in wetland area by approximately 25%, it would be expected that ...

math

chemistry
4.3 cm would be 1.69 in

statistics
A multiple-choice quiz has 15 questions, each with 4 possible answers of which only 1 is the correct answer. What is the probability that a student gets 7 to 11 correct answer?

Solid Mensuration
A triangle has a base of 16 inches and an altitude of 8 inches. Find the dimensions of the largest rectangle that can be inscribed in the triangle if the base of the rectangle coincides with the base of the triangle.

Calculus
Thank You!!

Calculus
The balloon leaves the ground 80 ft. from an observer and rises vertically upward at 5 ft/s. (a) How fast is the balloon receding from the observer after 12 seconds? (b) find the corresponding acceleration? How do I sketch it? and what equation should I use? Please show the ...

Calculus
A man 5.5 ft tall walks away from a lamp post 10 ft high at the rate of 8 ft/s. (a) How fast does his shadow lengthen? (b) How fast does the tip of the shadow move? Can you please tell me what method/s you used to come up with a solution? I wasn't sure about the sketch I ...

Calculus
why was it multiplied to 10?

calculus
find the equation of the curve for which y'''=24x-6 if the curve passes through (-1,8) and is tangent to the line y=4x at (1,4). help please thanks :-)

calculus
if the driver of a car wishes to increase his speed from 20 mph to 50 mph while traveling a distance of 528 ft., what constant acceleration should he maintain?

calculus
a particle starts from rest and moves along a straight line with an acceleration equal to 24-15√t where distance and time are measured in terms of feet and seconds respectively. with what acceleration will the particle return to the starting point? help please thank you :-)

calculus
it's 904 ft. thank you :-)

calculus
a stone dropped from a balloon which was rising at the rate of 15 ft./sec. reached the ground in 8 seconds. how high was the balloon when the stone was dropped?

calculus
If the driver of a car wishes to increase his speed from 20 mph to 50 mph while traveling a distance of 528 ft., what constant acceleration should he maintain?

calculus
a particle starts from rest and moves along a straight line with an acceleration equal to 24-15√t where distance and time are measured in terms of feet and seconds respectively. with what acceleration will the particle return to the starting point?

calculus
A stone dropped from a ballon which was rising at the rate of 15 ft./sec. reached the ground in 8 seconds. how high was the ballon when the stone was dropped? please help :-) thank you

calculus

calculus
a parachutist falling at the rate of 15 ft./sec. drops a stone. if he was 904 ft. above the ground when the stone was dropped, how long would it take the stone to reach the ground?

calculus
Thank you very, very much. I'm really grateful.

calculus
a = 1/(t√t)

calculus
a particle moves according to the law a=1/t √t. if s=8 when t=1. and s=16 when t=4. find v when t=9.

SLCS
Paul and Juston are carrying a sack or rice weighing 6.02x10^2 N on a pole between them. If the pole is 2.0 m long and the load is .50m away from Juston,what force should each boy exert to make it equilibrium. Neclect the weight of the pole.

Nutrition
:can be converted to vitamin D, the answer is a.

Math
Serena is an account executive. She receives a base pay of \$18 an hour plus a 15% bonus for all the sales she generates. Last week she generated \$1,200 worth of business. What is the minimum number of hours she could have worked to make \$500?

Pharmacy Tech
ah ok so basically warnings- can cause these symtoms and adverse reactions- things that was observed during clinical trials? that would be the difference?

Pharmacy Tech
20.) To find out if a drug causes nausea, you would look in this section of the drug monograph. a) adverse reactions b) contraindications c) how supplied d) warnings I am leaning towards a but not sure..I could also think it could be d as well...am confused and i keep ...

physics
a gun converts 200J of stored energy into kinetic energy of the 0.02kg bullet. What is the speed of the bullet as it leaves the gun? If the gun is fired straight up, how high will the bullet go?

Physics
60mph converts into 26.82m/s, a= (0-26.82 m/s) -26.82 m/s but don't understand how to get answer in Newtons which are kg m/s^2

math
solve: 2x + 5 = 3x - 9

Trig
How do you derive this identity? Cos(t)=1-sin^2(t/2)

Math
{0,9700} and {6,109000} just like in a normal x-y equation, slope={109000-97000}/{6-0} =12000/6=2000 using {0,97000} ,which would be the y-intercept y=2000x+97000

MicroEconomics
3000

Persuasive Essay
Should violent video games be prohibited from sale?

calculus
Use iterated integral to find the area enclosed by r=2sin2(theta). How do i graph this?

calculus
Z=square root of(x^2+y^2) + xy Find the partial derivatives: x, xx, y, yy, xy. Thanks.

math
The domain and range of ln(4-x-y). Thanks.

math
Z=square root of (x^2+y^2) + xy Find the partial derivatives: x, xx, y, yy, xy. Thanks.

math
But why wouldnt the answer be just xe^y cos(xy)? if the partial derivative with respect to x is just ye^y cos(xy).

math
The partial derivative with respect to y for z=e^y sin(xy) is: zy= xe^y cos(xy) + e^y sin(xy) How do i get to this answer? Thanks.

math
Find the rectangle with the maximum area inside the ellipse x^2/16 + y^2/4=1. Thanks.

physics
If a 2kg car with a momentum of 12kg m/s collides with a stationary 4kg car, the total momentum after the collision will be?

Statistics – Lab Week 2
Thanks for the help...

Statistics ¨C Lab Week 2
The corelation coefficient is: r=0.9982 Step 1: Find X⋅Y, X^ 2 and Y ^2 as it was done in the table below. X Y X⋅Y X⋅X Y⋅Y 67.273 69.78 4694.30994 4525.656529 4869.2484 0.764 1.40 1.0696 0.583696 1.96 2.533 4.21 10.66393 6.416089 17.7241 63.000 61.00 ...

Statistics – Lab Week 2
11. Using the empirical rule, 68% of male heights should be between what two values? Either show work or explain how your answer was calculated.

Algebra
x(a+b+2) (x+3)(a+b)

equations
Exact result: 3N/16 = 24

math
True

Algebra
Solution for the variable b b=a

Science

physics
The vertical acceleration of a projectile A)equals g pointing sometimes upwards and other times downwards. B)equals g pointing upwards C)is zero. D)equals g pointing downwards E)continuously increases. Thanks!

physics
Thanks!

physics
A child, who is 45 m from the bank of a river is being carried downstream by the river's swift current of 1.0 m/s. As the child passes a lifeguard on the river's bank, the lifeguard starts swimming in a straight line until she reaches the child at a point downstream. ...

algebra
what is the inner diameter of a washer whose outside is l inch and thickness is 3/16 inche

Math
If a hallway is 90 feet long & 7 feet wide and it takes 1/2 ounce of cleaning solution to clean 1 square foot, how much cleaning solution is needed to clean the hallway?

physics
croquet ball must have a set mass of 0.50 kg. a red ball moving at 10.0 m/s, strikes an at-rest green ball head on. The red ball continues moving at 1.5 m/s after it hits the green ball. What is the final speed of the green ball?

Milford DE
#6 Plot Story map for the other wife

Pre Algebra
cone

Visual Basic
Write a statement that assigns the length of an array named strAddressBook to a variable named intAddressCount.

Computers
Write a statement that assigns the length of an array named strAddressBook to a variable named intAddressCount.

chemistry
very hot sinc will react with steam to form zinc oxide and hydrogen. If 5.4 liters of hydrogen was used to use up 20 g of zinc completely. What is the percent yield of this process

20th century Europe
The European dominance was replaced by what is also known as the globalization?

20th century Europe
to describe the international events and the economic, intellectual and cultural developments in the twentiet-first century

20th century Europe
The 20th century European dominance was replaced by what?

american government
the professional qualification model in the selection of judges holds that

Science >.<
if a wave is traveling at 60cm/second and has a wavelength of 15cm,what is the frequency

Using the price per dinner that you determined in the previous question, calculate the following. If Epicure offers a \$1-off coupon in a newspaper advertisement, what markdown percent does the coupon represent? (Round percent to the nearest tenth.)

Physics
A rock is ejected vertically upward at 40 m/s. At what time is the rock moving at 20 m/s upward.

math
70-40=30 30/250=x/1000 30000/250=120 A) 120

algebra
Question Four x - 7y = 15 -3x + 21y = - 45

economics
Bob and his dad visited the hardware store on Saturday. They observed the following transactions: Mr. Harris bought 4 for 0.50, Mrs. Clarke bought 21 for \$1.00, Mr. Montaro bought 1,134 for \$2.00 and Ms. Park bought 450 for \$1.50 What were they buying?

American National government
According to the trustee model of representation, members of Congress must do what

math
find the value of x in the equation 6x +4(70-x)=300

Intro to Logic
10. A strongly supported claim in science should be regarded as

math
simplifying expressions

macro-economics
1.In an attempt to curb the problem of unemployment and win the forthcoming elections the government of the republic of zambia has decided to hire unemployed workers who had previously been receiving unemployment benefits as government employees and will now pay them to do ...

political science

science
What is science

chemistry
balance net Ionic solution AgNo3 + NaOH

political science
is politics an art or a science? give proper reasons for chosen side.(its an essay)

political science
what are the argument for and against politics being a science

political science
Is politics a science or not? Give a reasons for answer

economics
John has a job that requires him to travel 3 of every 4 weeks. He has an annual budget and can travel either by train or by plaine. The airline on which he typically flies has a frequent traveler programme that reduces the cost of his tickets according to the number of milels ...

economics
John has a job that requires him to travel 3 of every 4 weeks. He has an annual budget and can travel either by train or by plaine. The airline on which he typically flies has a frequent traveler programme that reduces the cost of his tickets according to the number of milels ...

Being inventory of 12 sets of paints at a cost of \$1.50 each. During the year the store purchased 4 sets at \$1.60, 6 sets at \$2.20, 6 sets at \$2.50, and 10 sets at \$3.00. By the end of the year, 25 sets were sold. Caculate the number of paint sets in stock and the cost of ...

Lee Corp. purchased 10 key chains on January 1, 2010 for \$9.00 each and 5 key chains were purchased on December 1, 2010 for \$10.00. Seven were sold. What would be the inventory amount for LIFO, what would be the inventory amount for FIFO

Assume you lease a \$45,000 BMW. Using a straight- line method with a 3- year ueful life and is a \$16, 675 residual value, what is the book value of the BMW after the first year?