Friday

October 24, 2014

October 24, 2014

Total # Posts: 169

**Chemistry**

An electrical heater is used to supply 200.0 J of energy to a 30.0 g sample of water, originally at 285.0 K. Determine the final temperature in degrees Kelvin. (the specific heat capacity for water is 75.291 Jmol-1K-1)
*October 21, 2014*

**Chemistry**

Why 22.4?
*October 21, 2014*

**Chemistry**

for that reaction and its kj
*October 21, 2014*

**biology**

Where is the location of the phosphatase enzyme in the digestive system. There is no site that i can find that can provide an answer...
*October 19, 2014*

**physics**

A block of mass m is pushed along a horizontal table by a force F= 70 N a an angle 55 degrees with the horizontal. The coefficient of kinetic friction is 0.3 Write Newtons second law using vectors. Write newtons second law using x scalar components
*October 17, 2014*

**Chemistry**

PLEASE help because I'm really confused on how to do the entire thing. I don't know how to find the mL. Am I suppose to do anything with the 250mL? A person stops in every day and orders 250 mL of house coffee at precisely 95°C. but enough milk at 10°C to drop ...
*September 25, 2014*

**math**

How would I go about dividing. -20 divided by (-2 1/2)
*September 21, 2014*

**Math**

167.53
*September 10, 2014*

**CHEM 1A**

Sweet. Thank you. I was real close. I was just calc ing the moles wrong at the end. Thanks again
*September 6, 2014*

**CHEM 1A**

Can someone please help me..... I have limited reactant formula problem. I am completely lost. 2Ca(s) + O2(g) ----> 2CaO(s) Calculate the mass of Calcium Oxide that can be prepared from 6.87g of Ca and 4.58g of O2. I calculated 2Ca to .171mol and O2 to .286mol, I am lost ...
*September 6, 2014*

**6th grade math**

Think about your number line starting at 0 from left to right. Negative numbers are always less than positive. Integers are numbers, whole numbers. you know least to greatest on your positive, right? Negative numbers are just reversed....
*September 5, 2014*

**CHEM 1A**

Sweet, Thank you....
*September 5, 2014*

**CHEM 1A**

Balanced equation, 4KNO3(s) ----->2K2O(s) + 2N2(g) + 5O2(g) To produce 51.8kg of O2, How many moles of KNO3 must be heated? How many grams of KNO3 must be heated? Do you calculate like KNO3 and O2 is just one mole or do you divide 4/5 at the end of the equation? 51.8kgO2 x ...
*September 5, 2014*

**7th grade Math**

There are 50 questions on a test. If a 60% is considered passing, how many questions do you have to get right to pass?
*October 29, 2013*

**Mathematics**

Is 27.38452... a real and a rational number?
*October 22, 2013*

**Math**

How do you write the number 339.4 X 10 -10 in scientific notation?
*August 27, 2013*

**Math**

If the length and width of a triangle are tripled, what is the effect on the area?
*August 27, 2013*

**Math**

Which expression represents the number in the pattern where "p" is the position of the number in the pattern? 20, 24, 28, 32, 36 a. 4(p +3) b. 4p - 4 c. 4p + 4 d. 4 (p+4)
*August 27, 2013*

** Physics**

A ball with a mass of 0.25 kilogram is swung on the end of a rope that is 3.0 meters long. The ball travels with a linear velocity of 10.00 meters per second. What centripetal force is acting on the ball?
*May 29, 2013*

**Chemistry **

A gas occupies 275 ml at 0°C and 610 Torr. What final temperature would be required to increase the pressure to 760 Torr, the volume being held constant?
*May 2, 2013*

**physics**

Bill has a mass of 83.6 kg. Jane has a mass of 51.0 kg. If they are seated 4.3 m apart, how much gravitational force attracts them?
*April 23, 2013*

**Chemistry **

A marathon runner will burn 1.25x10^7 j during a race. If the calorie content of 12.0 oz. of Gatorade is 80.0 kilocalories, how many ounces of Gatorade must the runner drink to provide enough energy for the race? Note: 1 Calorie=4.184j and "kilo"= 10^3
*April 20, 2013*

**Chemistry **

An alloy contains 39.5 mass% silver (Ag) and has density og 7.86 g/ml What volume of alloy would be needed to contain 12.0g of pure Ag?
*April 20, 2013*

**Chemistry**

A student uses 57.4 ml of 0.2m of RbOH to titrate 25.0ml of HcLo3. What is the concentration of HcLo3?
*April 18, 2013*

**physics**

Just wanted to say a quick thanks to Steve and Damon, figured it all out, thanks guys, awsome!!!
*April 12, 2013*

**physics**

I gave the wrong answer at first. Sorry.
*April 12, 2013*

**physics**

Sorry the answer they have is 60.5 degrees east of of north or 29.5 degrees north of east. There would be two vectors right, so do you take the degrees from the resultant? Thanks Damon, I do not nothing about this stuff at all. The question says my answer should be found by ...
*April 12, 2013*

**physics**

A boat is traveling on a bearing of 25 degrees East of North at a speed of 4 knots (a knot is 1.852 km/h). After traveling for 3 hours, the boats heading is changed to due South and it travels for an additional 2 hours at 5 knots. Using a Vector diagram, what is the resultant...
*April 12, 2013*

**physics**

Sorry Steve wrong answer, they got 60.5 degrees east of north or 29.5 degrees north of east. Sorry about that.
*April 11, 2013*

**physics**

Hi Steve, thank you. The answer for the question 81.4N at 84 degrees west of north or 6 degrees north of west. But they show no work to get the answer. I am still confused, please help me a little more. Thanks Steve.
*April 11, 2013*

**physics**

A boat is traveling on a bearing of 25 degrees East of North at a speed of 4 knots (a knot is 1.852 km/h). After traveling for 3 hours, the boats heading is changed to due South and it travels for an additional 2 hours at 5 knots. Using a Vector diagram, what is the resultant...
*April 11, 2013*

**physics**

A boat is traveling on a bearing of 25 degrees East of North at a speed of 4 knots (a knot is 1.852 km/h). After traveling for 3 hours, the boats heading is changed to due South and it travels for an additional 2 hours at 5 knots. Using a Vector diagram, what is the resultant...
*April 10, 2013*

**physics**

Hi, I am completely new to this, and missed a lot of classes due to hospital trips. Trying to cathc up but there is no sample question in my text. I dont really know how to get the numbers to make the vectors. Can you lead me in the right direction, would be very much ...
*April 7, 2013*

**physics**

A boat is traveling on a bearing of 25 degrees East of North at a speed of 4 knots (a knot is 1.852 km/h). After traveling for 3 hours, the boats heading is changed to due South and it travels for an additional 2 hours at 5 knots. Using a Vector diagram, what is the resultant?
*April 7, 2013*

**physics**

A boat is traveling on a bearing of 25 degrees East of North at a speed of 4 knots (a knot is 1.852 km/h). After traveling for 3 hours, the boats heading is changed to due South and it travels for an additional 2 hours at 5 knots. Using a Vector diagram, what is the resultant?
*April 6, 2013*

**physics**

A boat is traveling on a bearing of 25 degrees East of North at a speed of 4 knots (a knot is 1.852 km/h). After traveling for 3 hours, the boats heading is changed to due South and it travels for an additional 2 hours at 5 knots. Using a Vector diagram, what is the resultant?
*April 5, 2013*

**Physics**

I am trying to help my step son who missed half of physics class due to a funeral. A laser beam is being shot through two different materials that have been stuck together. if theta 1 = 65.5 and theta 2 = 49.8 what is the index of refraction? (I got 1.2 which is correct) but ...
*April 4, 2013*

**science**

: how much work is done by 0.020 meters squared of gas if its pressure increases by 2.0 multiplied by 10 to the 5th power Pa and the volume remains constant ?
*February 27, 2013*

**Physics**

A rowboat passenger uses an oar to push the boat off the dock by exerting a force of 40.0 N for 3.0 s. What impulse acts on the boat? What formula do I use?
*February 16, 2013*

**Math**

Mrs coopers 5th grade class has 11 more girls than boys. There are 35 students in all. How many girls are there?
*January 24, 2013*

**math**

what amount of principal would yield an interest of $36 in 3 years at a 3% simple interest rate?
*January 24, 2013*

**Science: Physics**

A force of 50 N directed at an angle of 45 degrees from the horizontal pulls a 70 kg sled across a frictionless pond. The acceleration of the sled is most nearly (sin 45 degrees = cos 45 degrees = 0.7).
*December 1, 2012*

**physics**

what is the frequency of wavelength 5.5cm travelling at 2 a speed of 1.6 m\s?
*November 19, 2012*

**physics**

A class of 11 students taking an exam has a power output per student of 122 W. Assume that the initial temperature of the room is 18.8oC and that its dimensions are 6.40 m by 14.5 m by 3.50 m. What is the temperature of the room at the end of 54.0 min if all the heat remains ...
*November 10, 2012*

**Chemistry**

Tell how to synthesize each compound. A. Ni(OH)2 B. MgSO4 C. KNO3
*October 26, 2012*

**physcis**

a flight attendant pulls her 70 kg flight bag in an airport terminal holding the handle 50 degrees above the horizontal. she pulls the bag a distance of 200 m while exerting a 40 n force acting along the handle with a constant speed how much work does the flight attendant ...
*October 20, 2012*

**Algebra**

The length of a rectangle is 5 less than twice the width. Find the dimensions if the perimeter is 110?
*October 15, 2012*

**Physics**

When you see a traffic light turn red, you apply the brakes until you come to a stop. Suppose your initial speed was 12.9 m/s, and you come to rest in 35.0 m. How much time does this take? Assume constant deceleration. What equation do I use to solve this problem? You can show...
*October 4, 2012*

**math**

90 volts are applied to a circut with 3 resistors resistor 1=20 ohms resistor 2=40 ohms and resistor 3=60 ohms how much power will be dissipated by resistor 1
*September 19, 2012*

**Chemistry**

How many moles of H_2 are needed to produce 13.27g of NH_3?
*September 19, 2012*

**Physics**

Two identical masses are connected by a (massless, stretchless) string across a (massless, frictionless) pulley. The mass on the right is held so that the string connected to it is horizontal. Everything is initially at rest; the tension is the string is zero. The mass on the ...
*August 10, 2012*

**Physics**

Bob, AKA smart guy, I already figured it out thank you very much. You obviously didn't read the question as it says don't use derived equations from the textbook. Wouldn't you assume conservation of energy and momentum equations are in the book?
*August 10, 2012*

**Physics**

A low friction cart of mass m, traveling at speed v, collides (perfectly) elastically with a cart of triple the mass, initially at rest. What is the result of this collision? (What are the final, after-collision velocities?) Do NOT use the derived equations from the textbook. ...
*August 10, 2012*

**Physics**

A flatbed truck with a box sitting on the bed accelerates from rest on level ground. The truck’s speed as a function of time is 15t –2t^2 during this acceleration. The truck reaches its maximum speed and cruises along at this speed for 4 minutes. It then slows to a ...
*August 10, 2012*

**Physics**

A 750 kg car traveling 22.0 m/s due north crashes into a 1500 kg truck traveling 20 m/s due west. The two vehicles become locked together and travel 19.0 m before stopping. Find the average frictional force (magnitude and direction) that brings the two to a stop.
*August 10, 2012*

**Physics**

The wind blows a 0.50 kg Styrofoam box, initially at rest, across level ground and then up an incline where it comes to a rest. The box slides 6.0 m on level ground before sliding up the 20.0 Ovincline. If the effective coefficient of friction between the ground and the box ...
*August 9, 2012*

**Physics**

Some object moves 220.0 m at an angle of 42° north of west. During this motion, a 68.0 N force acts on the same object, doing +5460.0 J of work on the object. Assuming the force is applied horizontal to ground, what is this force’s orientation? Is there more than one ...
*August 9, 2012*

**Physics**

A block of mass m has a spring –spring constant k and length L –connected, vertically, to the bottom. The block is dropped from height h, towards the floor. Assuming the spring is stiff enough that it does not compress fully at the floor, what is the closest distance...
*August 9, 2012*

**Physics**

Box, mass m 1 , at rest against a compressed spring, spring constant k and compression of Δx, at the top of a ramp, height h, is released. It slides down the ramp, angle θ, with friction, coefficient μ. Half way down the ramp, it bumps into and sticks to another...
*August 9, 2012*

**Physics**

Jenn Suhr recently won the gold medal in this summer’s Olympic games in pole vault. Her record is 16 ft, 2 in. (She did less than that to win gold this summer.) If all of her gravitational potential energy came only from her kinetic energy, calculate (in m/s) the running ...
*August 8, 2012*

**Physics**

In the school cafeteria, a trouble-making child blows a 12.0 g spitball through a 25.0 cm straw. The force of her breath as a function of the distance along the length of the straw can be modeled as 10-50x^2-70x^3 where force is in newtons and x is in meters. (a) How much work...
*August 8, 2012*

**Physics**

A missile launcher, mass M, at rest on a horizontal track fires a missile, mass m, horizontally. a) If the launch speed of the missile is v o , what (effective) coefficient of (kinetic) friction is required in order to stop the launcher within x meters? (b) Missile launcher ...
*August 8, 2012*

**Physics**

A missile launcher, mass M, at rest on a horizontal track fires a missile, mass m, horizontally. a) If the launch speed of the missile is v o , what (effective) coefficient of (kinetic) friction is required in order to stop the launcher within x meters? (b) Missile launcher ...
*August 7, 2012*

**Physics**

A cart is coasting at a speed v A along a straight and level road. When ten percent of the wagon’s mass is thrown off the wagon, parallel to the ground, and in the forward direction, the wagon stops. However, if this same amount of mass is thrown out the back of the wagon...
*August 7, 2012*

**Physics**

A 5.0 kg shell is fired vertically upward. At its max height of 350.0 m, it explodes into 3 pieces. A 1.0 kg chunk lands 15.0 m away, 45 O due northeast from the launch site. A second 1.0 kg piece lands 25.0 m, 60 O south of east from the launch site. If all 3 pieces land at ...
*August 7, 2012*

**Physics**

A 140 g, 90.0 mph fastball comes across the plate very nearly horizontally and is batted at 90.0 mph at a 30.0O angle (above the horizontal) toward center field. (a) Determine the impulse (in N.s) acting on the ball. (b) If the impact time is 0.00080 s, determine the average ...
*August 7, 2012*

**Physics**

A 140 g, 90.0 mph fastball comes across the plate very nearly horizontally and is batted at 90.0 mph at a 30.0O angle (above the horizontal) toward center field. (a) Determine the impulse (in N.s) acting on the ball. (b) If the impact time is 0.00080 s, determine the average ...
*August 6, 2012*

**Physics**

A 125 kg flatbottomed boat is floating along at 5.0 m/s, headed east. Sally Sue, standing at one end of the boat, starts to walk at 2.0 m/s, also to the east. If Sally’s mass is 65 kg, what is the speed of the boat as she walks along?
*August 6, 2012*

**Physics**

A car, starting from rest, accelerates down a hill reaching 30.0 m/s in 6.00 s. During this time, the driver notices that the fuzzy dice hanging by a string from the ceiling is perpendicular to the ceiling. Find (a) the angle θ of the hill and (b) the tension in the string.
*July 24, 2012*

**Physics**

The weight of an object is the same on two different planets. The mass of planet A is sixty percent that of planet B. Find the ratio of the radii of the two planets, rA/rB
*July 24, 2012*

**Physics**

A box starting from rest, slides down an incline which makes an angle of θ above the horizontal. The incline has a maximum height of h above the platform on which it sits which is itself H above the ground. The box leaves the end of the ramp and platform's edge and ...
*July 24, 2012*

**Physics**

A 565 N mountain climber moves across a rope strung across a canyon. When she is more than halfway across, she notices the rope makes a 10 degree angle (from horizontal) behind her and a 25 degree angle (from horizontal) ahead of her. What are the tensions in the rope in front...
*July 24, 2012*

**math grade 12**

It is a beautiful sunny day at Canada’s Wonderland. The U.V. index for this day is 8, or high, so sunscreen is a must for all people. The effectiveness of sunscreen is indicated by the sunscreen protection factor (SPF). The higher the SPF number the fewer U.V. rays can ...
*July 23, 2012*

**math grade 12**

1 - .012 = .988 why did you do this?
*July 23, 2012*

**History**

The red is representing the flag of England (St George's Cross) and white to represent the French royal emblem. The red maple leaf has long been the emblem and symbol of Canada. The red bands on either side represent the Pacific and Atlantic oceans, red being one of ...
*July 7, 2012*

**Physics**

A 65kg box is sitting on a level surface, and a 208N force is pulling on the box to the right. find both the normal force and acceleration of the box
*July 7, 2012*

**physics**

suppose your car is on a 5% grade,if your car weighs 15,000N what is the component of its weight parallel to the road?
*July 7, 2012*

**algebra**

Determine the slope of a line passing through the points (2, 9) and (0.66, 9).
*July 3, 2012*

**Math**

On the leeward side of the island of Oahu, in the small village of Nanakuli, about 80% of the residents are of Hawaiian ancestry. Let n = 1,2,3.... represent the number of people you must meet until you encounter the first person of Hawaiian ancestry in the village of ...
*May 22, 2012*

**Math**

Suppose you have binomial trials for which the probability of success on each trial is p and the probability of failure is q= 1-p. Let k be a fixed whole number greater than or equal to 1. Let n be the number of the trial on which the kth success occurs. This means that the ...
*May 22, 2012*

**health**

what smoking bans were put in place between 1964 and 1988
*May 3, 2012*

**chemistry**

A 0.27 sample of a weak acid with an unknown was combined with 12.0 of 3.00 and the resulting solution was diluted to 1.500 . The measured of the solution was 3.95. What is the of the weak acid?
*April 17, 2012*

**physical science**

a race car having a mass of 2550 kg is accelerated by a force of 127,500n.what is the accelerration?
*February 15, 2012*

**physics**

A block with mass m =7.3 kg is hung from a vertical spring. When the mass hangs in equilibrium, the spring stretches x = 0.21 m. While at this equilibrium position, the mass is then given an initial push downward at v = 4.5 m/s. The block oscillates on the spring without ...
*February 6, 2012*

**chemistry**

Which number is the greatest number or significant digits 17.500 or 6.022 x 10^23
*February 4, 2012*

**chemistry**

calculate[OH-],[H+] of a .20 M solution of triethylamine Kb=4.0*10^-4
*January 22, 2012*

**social studies**

a young jorge washington-
*November 29, 2011*

**Algebra**

Need help factoring 7x^2 + 7x -20
*November 17, 2011*

**science**

Which two of the 12 science processes do you feel are the most important for students to understand early in their science studies?
*October 27, 2011*

**math modeling**

86 months
*October 25, 2011*

**chemistry**

A sample of gold is at a initial temperature of 350 k. Once dropped into a coffe cup calorimeter of heat capacity 400 k^-1 it contains 50 g of water at 300 k. Specific heat capacity is 0.129 for gold and 4.18 for water. what is the final temp of all gold, coffee cup, and water.
*October 12, 2011*

**chemistry**

A sample of gold is at a initial temperature of 350 k. Once dropped into a coffe cup calorimeter of heat capacity 400 k^-1 it contains 50 g of water at 300 k. Specific heat capacity is 0.129 for gold and 4.18 for water. what is the final temp of all gold, coffee cup, and water.
*October 11, 2011*

**physics**

A ball is thrown horizontally from a height of 18.18 m and hits the ground with a speed that is 4.0 times its initial speed. What was the initial speed?
*October 10, 2011*

**math**

If there are 36 buttons in a jar and there are 3 times as many white buttons than red, how many of each are in the jar? What is the equation and how do I solve?
*September 29, 2011*

**Chemistry**

sodium carbonate trihydrate
*September 7, 2011*

**CHEMISTRY!!!!!!! HELP PLEASE:)**

1701.6
*September 7, 2011*

**physics**

A car is heading towards a brick wall at 80 km/hr, he starts breaking 30 feet away. What acceleration is required to avoid a collision?
*August 9, 2011*

**5th grade math**

average 98,76,83,91
*June 12, 2011*

**Chemistry**

a solution contains 0.133 g of dissolved lead. How many moles of sodium chloride must be added to the solution to completely precipitate all of the dissolved lead? what mass of sodium chloride must be added?
*May 14, 2011*

**physics**

hello
*April 4, 2011*