Wednesday

April 1, 2015

April 1, 2015

Total # Posts: 589

**Physics**

A radioactive substance decays from 2.0kg to 1.6kg in 156 days. How much will be left after 201 days?
*August 7, 2013*

**Physics**

A radioactive substance decays from 2.0kg to 1.6kg in 156 days. What is the decay constant and the half life of the substance?
*August 6, 2013*

**physics**

A granite column in a building is 8.50 m high and has a mass of 2.16 multiplied by 104 kg. (a) How much heat (J) is needed to increase its temperature by 10.5°C, given its specific heat is 0.200 kcal/kg·°C? (b) What is its change in length (m) if its coefficient...
*July 24, 2013*

**physics**

A certain heat engine does 8.0 kJ of work and dissipates 8.00 kJ of waste heat in a cyclical process. (a) What was the heat input to this engine? (b) What was its efficiency?
*July 24, 2013*

**physics**

I don't know which are the "area" and "V". Can you show me the steps. Thanks.
*July 24, 2013*

**physics**

A hand-driven tire pump has a 2.50 cm diameter piston and a maximum stroke of 31.0 cm. (a) How much work do you do in one stroke if the average gauge pressure is 2.40 multiplied by 105 N/m2 (about 35 psi)? (You may consider this an isothermal process.) (b) What average force ...
*July 24, 2013*

**Physics**

A particular brake design can apply a force of 2000 N. If you wish to have a deceleration of 5m s1, what is the largest car weight you can use with this design?
*July 22, 2013*

**physics**

A 3.00 g lead bullet traveling at 640 m/s strikes a target, converting its kinetic energy into thermal energy. It's initial temperature is 40.0°C. Find the available kinetic energy of the bullet. Find the heat required to melt the bullet.
*July 21, 2013*

**physics**

The formation of condensation on a glass of ice water causes the ice to melt faster than it would otherwise. If 7.40 g of condensation forms on a glass containing water and 210 g of ice, how many grams will melt as a result? Assume no other heat transfer occurs. Use the heat ...
*July 21, 2013*

**physics**

(a) How many kilograms of water must evaporate from a 60.0 kg woman to lower her body temperature by 0.750°C?
*July 21, 2013*

**physics**

The sun radiates like a perfect blackbody with an emissivity of exactly 1. (a) Calculate the surface temperature(K) of the sun, given it is a sphere with a 7.00 multiplied by 108 m radius that radiates 3.80 multiplied by 1026 W into 3 K space. (b) How much power(W/m^2)does the...
*July 21, 2013*

**Physics**

The sun radiates like a perfect blackbody with an emissivity of exactly 1. (a) Calculate the surface temperature(K) of the sun, given it is a sphere with a 7.00 multiplied by 108 m radius that radiates 3.80 multiplied by 1026 W into 3 K space. (b) How much power(W/m^2)does the...
*July 20, 2013*

**physics**

The "steam" above a freshly made cup of instant coffee is really water vapor droplets condensing after evaporating from the hot coffee. What is the final temperature of 200 g of hot coffee initially at 90.0°C if 2.00 g evaporates from it? The coffee is in a ...
*July 20, 2013*

**Physics**

On a certain dry sunny day, a swimming pool's temperature would rise by 1.60°C if not for evaporation. What fraction of the water must evaporate to carry away precisely enough heat to keep the temperature constant? (Lv =2430kJ/kg or 580kcal/kg)
*July 20, 2013*

**physics**

The formation of condensation on a glass of ice water causes the ice to melt faster than it would otherwise. If 8.80 g of condensation forms on a glass containing water and 170 g of ice, how many grams will melt as a result? Assume no other heat transfer occurs. Use the heat ...
*July 20, 2013*

**physics**

A slab of a thermal insulator with a cross-sectional area of 115 cm2 is 4.00 cm thick. It is made out of red brick with thermal conductivity 0.600 J/s∙m•C°. The temperature difference between opposite faces is 95.0 C°. Calculate the following: (a) The heat ...
*July 20, 2013*

**physics**

A 2.60 kg steel gas can holds 15.0 L of gasoline when full. What is the average density of the full gas can, taking into account the volume occupied by steel as well as by gasoline?
*July 18, 2013*

**physics**

A 2.60 kg steel gas can holds 15.0 L of gasoline when full. What is the average density(kg/m^3)of the full gas can, taking into account the volume occupied by steel as well as by gasoline?
*July 18, 2013*

**physics**

The greatest ocean depths on earth are found in the Marianas Trench near the Philippines, where the depth of the bottom of the trench is about 11.0 km. Calculate the pressure(atm)due to the ocean at a depth of 10.1 km, assuming sea water density is constant all the way down...
*July 18, 2013*

**physics**

A 2.60 kg steel gas can holds 15.0 L of gasoline when full. What is the average density of the full gas can, taking into account the volume occupied by steel as well as by gasoline?
*July 18, 2013*

**physics**

A 2.60 kg steel gas can holds 15.0 L of gasoline when full. What is the average density of the full gas can, taking into account the volume occupied by steel as well as by gasoline?
*July 18, 2013*

**Physics**

A train initially travelling at 30ms^1 decelerates at 4ms^2. (a) What time will it take to slow to 5m s^1? (b) What distance will it have travelled when it has slowed to 5ms^1?
*July 16, 2013*

**Physics**

An object accelerates from 10m/s to 16m/s in 10 secs. What will be the object’s velocity after 1 minute?
*July 16, 2013*

**Science**

A picture os the salor sysmty
*June 22, 2013*

**Arithmetic Sequence Help!**

The sum of 3 consecutive terms of an arithmetic sequence is 165. The second of these terms is 11 times the first. Find the 3 terms From what I gathered: S(3) = 165 t(2)= 11(t1) The given formulas are: Sn= n/2[2a+(n-1)d] and tn=a+(n-1)d I have no idea how to continue.
*June 17, 2013*

**Physics**

scroll all the way to the bottom: lakeheadschools.ca/scvi_staff/brecka/Gr11_physics_web/downloadable_content/unit12/Text12/phys11_12_6.pdf How do you figure out which way the motor will spin (figure 12)? And how do you figure out which way the loop will rotate? And to answer 1...
*June 10, 2013*

**Physics**

lakeheadschools.ca/scvi_staff/brecka/Gr11_physics_web/downloadable_content/unit12/Text12/phys11_12_5.pdf
*June 10, 2013*

**Physics**

Scroll all the way to the bottom in the link I'll provide below and there will be diagrams for which my questions/answers are based on. I'm having trouble applying the "right hand rule" to 1. c) Also, for 1.a) I think the magnetic field lines should go around...
*June 10, 2013*

**Calculus**

A helium balloon rises vertically at 3.5m/s as the wind carries it horizontally at 5.0m/s. What is the resultant velocity of the balloon?
*May 31, 2013*

**Bibliography**

In a bibliography, what is the title of the website? For example, for mises[dot]org/daily/3663 (please replace the [dot] with a period) is the title of the website "Mises[dot]org", "Ludwig von Mises Institute", or neither? I always thought it was, for ...
*May 29, 2013*

**math**

At an airport, a flight controller was in a tower 40m above the ground. When she first observed a plane it was at an angle of elevation of 12 (degrees) from her line of sight and flying at a constant altitude (height) The plane had a constant speed of 360km/h Eight seconds ...
*May 19, 2013*

**Math**

ted sells his homemade peanut butter for 1.60 a jar at the local farmers Market the jar is 8 cm in diameter and 10 cm high he decides he will also sell peanut butter in jats that are 16 cm in diameter and 20 cm high.What should he charge if he uses the same price per cubic ...
*May 15, 2013*

**Math**

a manufacturer makes right triangular prisms like the one shown for refracting light. They will be packed in boxes 12.5 cm long, 2.5 cm wide and 22.5 cm high. How many prisms can fit the box?
*May 15, 2013*

**Math**

a manufacturer makes right triangular prisms like the one shown for refracting light. They will be packed in boxes 12.5 cm long, 2.5 cm wide and 22.5 cm high. How many prisms can fit the box?
*May 15, 2013*

**Math**

a rectaguler tub with dimesions 2m x 1m x 0.5 is filled with water using a pail of radius 0.1m and height 0.35. How many pails of water will be required? give yor answer to the nearest pail.
*May 15, 2013*

**Math**

5. The pet shop down the street owns 84 fish. The ratio of birds to fish is 3 to 7. How many birds are in the pet shop?
*May 13, 2013*

**chemistry**

what's the T Kb what would the molality be plugged in for the equation
*May 13, 2013*

**chemistry **

a sample of 15.00 g of an unkown metal chloride, MCl2 is dissolved in 75.0 mL water. the boiling point of the resulting solution is measured at 102.37 degrees C. what is the identity of the metal M.
*May 13, 2013*

**Physics**

A ray of light of vacuum wavelength 550 nm traveling in air enters a slab of transparent material. The incoming ray makes an angle of 34.3◦ with the normal, and the refracted ray makes an angle of 18.9◦ with the normal. Find the index of refraction of the ...
*May 6, 2013*

**Math**

What is the dollar amount for the cement needed for a sidewald that is 4 inches thick, 3 feet wilde, and 40 feet long if the cement is sold for $76 petr cubic yard. Calculate the problem using fractions to avoid rounding errors caused by repeating decimals.
*May 6, 2013*

**Stat**

A student takes a 10-question true-false and randomly guesses the answer to each question. Suppose a correct answer is worth 1 point, an incorrect answer is worth -.5 points. Find the probability the student gets 7 or more points.
*May 4, 2013*

**math (Algebra)**

I was wondering if someone can help me with this question ,please... (2r5+r3)^2 r=radical
*May 1, 2013*

**.MATH.**

If about 3000 of every recall model of a vehicle actually need rework, what is the probability that your (recalled) car will not need a rework if there are 120000 cars of that model sold, and if 1000 of them are already off the road (this is a monkey wrench!). State your ...
*April 30, 2013*

**Math**

a 2-month note for $4,500 was drawn on July 3 at 8%. If money is worth 9%, find the present value of the note on the day it was made.
*April 30, 2013*

**geometry**

you plan to carpet 468ft of space. carpet costs $26.75 per square yard and the tax is 7%. the carpet is sold in 12 ft rolls. what is the cost of the carpet?
*April 25, 2013*

**geometry**

the bore of an engine cyclinder is the diameter of the piston and the stroke is the distance that the piston will travel up the cyclinder wall. The displacement is the volume of space that the piston goes thru. If the piston is 3.97" in dia. and the stroke is 4" what...
*April 25, 2013*

**please help geometry**

you need to find the length of a broken automitive belt. the belt ran around 2 pulleys whose centers were 11 in apart. one of the pulleys is 4" dia. and the other is 6" dia. what is the totoal length of the belt needed to connect thr pulleys?
*April 25, 2013*

**geometry**

how many 3"x4"x6" boxes will fit in a 2'x3'x8' container?
*April 25, 2013*

**bonds**

YOU WANT TO BUY A TREASURY BILL WHOSE FACE VALUE IS $20000 IN 30 DAYS. THE INTEREST RATE IS 4.61%. HOW MUCH WILL YOU HAVE TO PAY FOR THE BILL?
*April 11, 2013*

**7th grade math/ geometry**

a costruction crew is repairing a 201 foot long section of a highway. The road is 8 feet wide and the concrete must be poured to the depth of 6 inches. How many cubic feet will be required for the repair?
*April 8, 2013*

**Life orientantion**

Describe 5 factors of Hiv
*April 8, 2013*

**algebra**

To balance a seesaw, the distance, in feet, a person is from the fulcrum is inversely proportional to the person's weight, in pounds. Peter, who weighs 150 pounds, is sitting 3 feet away from the fulcrum. If Joey weighs 90 pounds, how far from the fulcrum should he sit to ...
*April 7, 2013*

**Math**

The weather forecast states that there is a 70% chance of rain tomorrow. Which of the "definitions" of probability is relevant to this statement and explain why?
*April 6, 2013*

**Math**

I get it , Thanks for everything
*April 6, 2013*

**Math**

Or could be 3√5/4*3 = 6√5.
*April 6, 2013*

**Math**

Thank you for your answer but I was thinking that the answer will be √9.5/12 then 3√5/12 and I do not know what to do with the denominator "12".
*April 6, 2013*

**Math**

Simplify the expression (square root) √45/144 Thanks.
*April 6, 2013*

**Physics**

A spring with a spring constant of 35.0 N/m is attached to diﬀerent masses, and the system is set in motion. What is the period for a mass of 34 g? Answer in units of s
*April 2, 2013*

**Physics**

A spring with a spring constant of 35.0 N/m is attached to diﬀerent masses, and the system is set in motion. What is its period for a mass of 2.4 kg? Answer in units of s
*April 1, 2013*

**Chemistry**

Find the Qsp when 9 drops of 0.014 M Na2CO3(aq) are added to 25 mL of 0.003 M AgNO3(aq). The solubility product of Ag2CO3 is 6.2 × 10−12. Assume 20 drops per milliliter.
*March 30, 2013*

**Math**

47 Fahrenheit = Celsius give answer in decimal form, to the nearest tenth?
*March 28, 2013*

**Geometry**

The length of one base of a trapezoid is 19 inches and the length of the median is 16 inches. Find the length of the other base.
*March 22, 2013*

**Geometry**

Abcd is an isosceles trapezoid with a(10,-1) b(8,3) and c(-1,3). Find the coordinates of d
*March 22, 2013*

**Geometry**

Thank you so much!
*March 21, 2013*

**Geometry**

For diagonals of square Abcd intersect at e . If ae =2x+6 and bd =6x-10 find ac
*March 21, 2013*

**Chemistry**

How many moles of NaCl are in 2.00mL of 1.00M NaCl?
*March 21, 2013*

**math**

A basket contains 15 red numbered balls and 10 white numbered balls. A sample of five balls is selected. How many samples contain three red balls and two white balls? Explain your answer.
*March 18, 2013*

**Chemistry**

A solution has a mass of 95.00g and a density of 2.147 g/mL. What is the volume of the solution?
*March 14, 2013*

**Physics**

A proton moves eastward in the plane of Earth’s magnetic equator so that its distance from the ground remains constant. What is the speed of the proton if Earth’s magnetic ﬁeld points north and has a magnitude of 5.2 × 10−5 T? The acceleration of ...
*March 6, 2013*

**Physics**

A proton moves eastward in the plane of Earth’s magnetic equator so that its distance from the ground remains constant. What is the speed of the proton if Earth’s magnetic field points north and has a magnitude of 5.2 × 10−5 T? The acceleration of gravity...
*March 6, 2013*

**RATIOS**

10.6 PESO IS $1 US DOLLAR. YOU HAVE 2500 PESO. YOU WANT TO EXCHANGE TO US DOLLAR. HOW MANY WOULD YOU GET?
*February 24, 2013*

**RATIOS**

A MODEL TRAIN IS 1;48 ON SCALE. THE ENGINE IS 13 5/8 INCHES. HOW MANY FEET IS THE ACTUAL ENGINE?
*February 24, 2013*

**Math **

Write the following complex number in polar form: z = 4 − 4i
*February 23, 2013*

**maths**

alissa is33 years old jacj is three times alyssa's age. How old are Jack and alyssa altogether?
*February 15, 2013*

**chemistry**

what is the specific heat of copper if the temperature of a 100g sample of copper is increased by 23C when 886J of heat is added ?
*February 11, 2013*

**MATH**

a car dealer sells a car with the following options: auto or manual transmission,standard or deluxe stereo,air or no air, manual or power locks, 15 or 16 inch tires, fabric or leather seats. how many different configurations can this car be sold in?
*February 10, 2013*

**MATH**

find a counterexample to prove the following is false: x is less than or equal to 2x
*February 10, 2013*

**MATH**

heres my equation: c(coat)+s(shirt)+t(tie)=$300 c=2s s=2t+40 i need to know how to solve this to get the cost of each item?
*February 8, 2013*

**math**

a coat,shirt and tie cost $300. coat costs twice as much as the shirt. shirt cost $40 more than twice the cost of the tie. what are the cost of each item?
*February 7, 2013*

**math**

a florist has 9 dozen roses. all are either red or white. he has 44 more red than white, how many white roses does he have?
*February 7, 2013*

**chem**

If 20.5 mL of a 5.256 M solution of benzoic acid is used in an experiment similar to experiment 4, how many grams of benzoic acid is in the starting solution? (molar mass of benzoic acid = 122.12 g/mol) Be sure to pay attention to significant figures. The answers are all in ...
*February 4, 2013*

**chem**

What does the concentration of the benzoic acid in the original liquid and the extracting liquid relate to after the extraction is completed? Answer a. The density of the original liquid. b. The density of the extracting liquid. c. The solubility of benzoic acid in each liquid...
*February 4, 2013*

**mathematics**

Mr. Collins is buying trsin tickets for $42 each. What is the total cost of the tickets? Use the distributive property to solve.
*December 22, 2012*

**Physics**

A 4.2 × 10^3 kg car accelerates from rest at the top of a driveway that is sloped at an angle of 18.4◦ with the horizontal. An average frictional force of 4.1×10^3 N impedes the car’s motion so that the car’s speed at the bottom of the driveway is 4...
*December 12, 2012*

**Chemistry**

What is the density of 3.40 liters of hci
*December 11, 2012*

**Physics**

A spring has a a constant of 650 N/m. How far must it be compressed to push a 4kg object on a friction-less surface to 3 m/s?
*December 7, 2012*

**Math**

This is from the actual problem - A consumer product testing lab tested 400 13-watt compact fluorescent light bulbs by turning them all on at once, leaving them on until they burned out, and recording the time-to-failure of each bulb. The test revealed a symmetric and mound-...
*December 5, 2012*

**Math**

What is the approximate percentile rank of a lightbulb that failed at 9000 hours if the number of lightbulbs is 400? The number of lightbulbs that lasted between 5400 and 9000 were about 326 lightbulbs. The mean is 7800 and the standard deviation is 1200 My guess was: ...
*December 5, 2012*

**Math**

The amount of a monthly electric bill (B, measured in $) depends on the amount of electricity used that month (E, measured in kWh). A typical public utility charges $0.12 per kWh for the first 300 kWh used, $0.17 per kWh for the next 600 kWh used, and $0.29 per kWh for any ...
*December 4, 2012*

**social studies**

What is the population of:Nile Valley,Ganges Valley and Eastern China
*December 3, 2012*

**Math**

ah, thanks... i'm only taking "liberal arts math", so have only done a little bit of calculus. how did you get this part? H(.2559) = appr 319.7 H(.744) = appr 312.7
*December 2, 2012*

**Math**

H(t) = 0.013t^2 + 0.81t + 316 + 3.5 sin 2πt Ah, the formula should have an exponent!
*December 2, 2012*

**Math**

The formula should actually be: H(t) = 0.013t2 + 0.81t + 316 + 3.5 sin 2πt
*December 2, 2012*

**Math**

Could someone explain how to find which months during the year the maximum/minimum points occur for this problem occurs? I think it's around May and Oct, but I don't get how to determine that on the graph The National Oceanic and Atmospheric Administration (NOAA) has ...
*December 2, 2012*

**Math**

how did you determine the maximum and the minimum?
*December 1, 2012*

**Math**

NOTE - the formula should be: H(t) = 0.013t^2 + 0.81t + 316 + 3.5 sin 2πt
*December 1, 2012*

**Math**

Could someone explain how to solve this math problem? I've graphed it, but I'm not sure how to solve the rest of the questions. The National Oceanic and Atmospheric Administration (NOAA) has been measuring atmospheric carbon dioxide concentations (in parts per million...
*December 1, 2012*

**Math**

Could someone explain what each part of this formula represents? H(t) = 0.058t^2 + 0.41t + 516 + 2.5 sin(2π)(t)
*November 30, 2012*

**chemistry**

What percentage of the Ba2+ in solution is precipitated as BaCO3(s) if equal volumes of 2.4*10^-3 M Na2CO3(s) and 1.1*10^-3M BaCl2(aq) are mixed
*November 21, 2012*

**world geography**

According to the Ministerial Conference on the Protection of Forests in Europe (MCPFEs), sustainable forest development is defined by these three criteria.
*November 20, 2012*

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