Wednesday

May 4, 2016
Total # Posts: 2,746

**math**

The distance between town A and town B was 210 km. At 9:20 pm, a bus set off from town A to town B and a car from town B to town A. The average speed of the bus was 60 km/h, and the average speed of the car was 80 km/h. a) Calculate the time at which the car passed the bus. b...
*April 28, 2016*

**math**

Ava made 100 paper cranes, and Brittany made 3/4 of paper cranes Ava made. Ava gave 9/20 of her paper cranes to Brittany. Then, Brittany gave 1/4 of her paper cranes to Ava. How many more cranes did Brittany have than Ava in the end?
*April 28, 2016*

**Physics**

a cube slides down a frictionless incline as shown and inelastically strikes a cube at the battom of the incline that's 1/2 (one-half) it's mass. The coeff. of restitution between the two masses is 0.7. If incline is 30 cm high and table is 90cm off floor, at what ...
*April 27, 2016*

**physics**

a cube slides down a frictionless incline as shown and inelastically strikes a cube at the battom of the incline that's 1/2 (one-half) it's mass. The coeff. of restitution between the two masses is 0.7. If incline is 30 cm high and table is 90cm off floor, at what ...
*April 26, 2016*

**Math **

A person plans to invest a total of $9000 in an account that pays 3% annual interest and another account which pays 8% annual interest. How much should be invested in each account so that the total interest for one year will be $580.
*April 25, 2016*

**math**

the power (P) generated in a electrical circuit is proportional to the square of the current ( L amps) . when the power is 108, the current is 6 amps. a_ write down the relationship between P,L and the constant of variation k . b_ calculate the value of k c_ calculate the ...
*April 24, 2016*

**math**

the length ( L cm) of an edge of a cube is proportional to the cube root of its mass ( M grams).It is known that if L= 15, then M=125. let K be the constant of variation. CALCULATE THE VALUE OF K
*April 23, 2016*

**Physics**

Blood flows in an aorta of radius 4.62mm at 35.0cm/s. Calculate the volume flow rate. Although the cross-sectional area of a capillary is much smaller than that of the aorta, there are many capillaries, so their total cross-sectional area is much larger. If all the blood from ...
*April 22, 2016*

**Physics**

Thank you!
*April 22, 2016*

**Physics**

I keep getting .154
*April 22, 2016*

**Physics**

Thank you so much! And What distance, d, from the edge of the table does the block hit the floor?
*April 22, 2016*

**Physics**

A 0.294-kg box is placed in contact with a spring of stiffness 3.792×102 N/m. The spring is compressed 1.42×10-1 m from its unstrained length. The spring is then released, the block slides across a frictionless tabletop, and it flies through the air. The tabletop ...
*April 22, 2016*

**Chemistry**

The pH of human blood needs to be between 7.35 and 7.45. You want to prepare a buffer solution that gives a pH of 7.40. You decide to use a sodium phosphate buffer: the acid is H2PO− 4 and the conjugate base is HPO2− 4 . You want the concentration of the acid to be...
*April 22, 2016*

**Math**

Thank you£¡
*April 22, 2016*

**Math**

I don¡¯t know how to slove this problem can someone help me£¿ The shorter leg of a 30¡ã60¡ã90¡ãtriangle is 2.5 feet long.Find the perimeter.
*April 22, 2016*

**Physics**

Consider a metal rod that is 1.42 m in length at a temperature of 14.4°C. The coefficient of linear expansion is 5.22×10-5°C-1. What is the change in length of the rod as temperature increases from 14.4°C to 52.0°C.
*April 21, 2016*

**Physics**

The volume flow rate in an artery supplying the brain is 4.59E-6 m3/s. If the radius of the artery is 5.33 mm, determine the average blood speed.
*April 20, 2016*

**Physics**

A block of mass M=0.525kg is floating stationary in a beaker of water. A string connected to the bottom of the beaker holds the block in place. The tension in the string is 7.10 N. The bottom of the block is floating a distance h=1.66cm above the bottom of the beaker. What is ...
*April 20, 2016*

**Chemistry**

I'm sorry the full question was: 1. If the initial H2PO− 4 concentration is 0.0100 M, what is the initial concentration of HPO2− 4 that will give a pH of 7.40? 2. What is the maximum molarity of acid that this buffer can neutralize without the pH dropping below...
*April 19, 2016*

**Chemistry**

The pH of human blood needs to be between 7.35 and 7.45. You want to prepare a buffer solution that gives a pH of 7.40. You decide to use a sodium phosphate buffer: the acid is H2PO−4 and the conjugate base is HPO2− 4. You want the concentration of the acid to be 0...
*April 19, 2016*

**Math**

A high school has 438 students with about the same number of males and females. Describe a simulation to predict how many of the first 50 students who leave school at the end of the day are female.
*April 19, 2016*

**Math**

Talia tossed a penny many times. she got 40 heads and 60 tails. she said the experimental probability of getting heads was 40 over 60. Explain and correct her error.
*April 19, 2016*

**math**

Shoot. I meant to say how to write this equation in standard form: y=(x+1)(x-1)(x-1)
*April 18, 2016*

**Precalculus**

A population of bacteria has exponential growth and will double after 10 hours. Find the growth rate to the nearest hundredth.
*April 13, 2016*

**Physics**

A spring loaded ballistic pendulum gun requires an increasing force to load. When loading a ball of mass 0.054 kg, the spring is compressed 7.00 cm, the gun is fully loaded, and the force required is 70.0 N. a) Calculate the work required to load the gun. b) Calculate the ...
*April 12, 2016*

**Physics**

A pendulum clock can be approximated as a simple pendulum of length 1.03 m and keeps accurate time at a location where g = 9.82 m/s2. In a location where g = 9.77 m/s2, what must be the new length of the pendulum, such that the clock continues to keep accurate time (that is, ...
*April 12, 2016*

**Stats**

{Exercise 7.11} The following data are from a simple random sample. 3, 8, 11, 6, 11, 15 What is the point estimate of the population mean? 9 What is the point estimate of the population standard deviation (to 1 decimal)?
*April 8, 2016*

**Geometry**

a jewlery box in the shape of a rectangle prism has a volume of 90in.3 and a height of 2 1/2 in, What are possible demensions for the length and width of base
*April 6, 2016*

**Physics**

A horizontal circular platform (m = 110.1 kg, r = 3.21m) rotates about a frictionless vertical axle. A student (m = 98.3kg) walks slowly from the rim of the platform toward the center. The angular velocity, omega, of the system is 3.9 rad/s when the student is at the rim. Find...
*April 6, 2016*

**chemistry**

If 5.40 kcal of heat is added to 1.00 kg of water at 100⁰C, how much steam at 100⁰C is produced? Show all calculations leading to an answer. Please help?
*April 6, 2016*

**chemistry**

You have two sealed jars of water at the same temperature. In the first jar there is a large amount of water. In the second jar there is a small amount of water. Using 3 -4 sentences explain how the vapor pressure of water in the first jar compares with the vapor pressure of ...
*April 6, 2016*

**Math**

Which hand has covered more distance from the 12 on a clock, the minute hand at 4:00 or the second hand at 15 seconds past? Write a fraction inequality to support your answer.
*April 5, 2016*

**Trig**

Find the exact values of sec(x)=7. I know that cos(x)=1/7. I know that sin(x)= sqrt(1-91/4900). I know that tan(x)=1. I know how to do the problem but I'm not really sure why, and I'd like to know. I got 4sqrt(3). Please help!
*April 1, 2016*

**Calculus**

I got the second answer. Still confused on the first one.
*April 1, 2016*

**Calculus**

Find the exact value of cot(arcsin(12/13)) and cos(arcsin(1.7/2)) I know that cos(arcsin(x))=sin(arccos(x))=sqrt(1-x^2). I'm having more difficulty with the first one. Please help! Thank you
*April 1, 2016*

**Calculus**

How do I tell the difference between a non conic function and a conic function by looking at an equation?
*March 31, 2016*

**chemistry**

A gas occupies 5.65 L at 808 torr and 17◦C. What volume will it fill if the pressure is changed to 730 torr and the temperature is raised to 51◦C?
*March 30, 2016*

**Algebra**

Find two consecutive even integers such that the square of the lesser integer increased by twice the greater integer is 364.
*March 30, 2016*

**Physics**

Just saw your reply, bobpursley. I will show you my work in a few minutes. Thank you
*March 30, 2016*

**Physics**

I got a, but can't figure out the rest of the questions. Please help! Thank you
*March 30, 2016*

**Physics**

A high-speed sander has a disk 5.70 cm in radius that rotates about its axis at a constant rate of 1120 revolutions per minute. a.) Determine the angular speed of the disk in radians per second. b.) Determine the linear speed of a point 2.40 cm from the disk's center. c.) ...
*March 30, 2016*

**Physics**

How do you turn revolutions into radians? Please help!
*March 30, 2016*

**Physics**

A wheel has a radius of 5.22 m. a.) How far (path length) does a point on the circumference travel if the wheel is rotated through an angle of 34.3°? b.) How far does a point on the circumference travel if the wheel is rotated through an angle of 34.3 rad? c.) How far does...
*March 30, 2016*

**Physics**

A pulsar is a rapidly rotating neutron star that continuously emits a beam of radio waves in a searchlight manner. Each time the pulsar makes one revolution, the rotating beam sweeps across the earth, and the earth receives a pulse of radio waves. For one particular pulsar, ...
*March 29, 2016*

**Physics**

A block of mass 0.61kg starts from rest at point A and slides down a frictionless hill of height h. At the bottom of the hill it slides across a horizontal piece of track where the coefficient of kinetic friction is 0.40. This section (from points B to C) is 4.73m in length. ...
*March 29, 2016*

**Physics**

In a skating stunt known as "crack-the-whip", a number of skaters hold hands and form a straight line. They try to skate so that the line rotates about the skater at one end, who acts as the pivot. The skater farthest out has a mass of 76.7 kg and is 6.18 m from the ...
*March 29, 2016*

**Physics**

A 9.37 kg monkey is hanging by one arm from a branch and swinging on a vertical circle. As an approximation, assume that the radial distance between the branch and the point where the monkey's mass is located to be 86.8 cm. As it swings through the lowest point on the ...
*March 29, 2016*

**Physics**

A car travels at a constant speed around a circular track whose radius is 2.59 km. The car goes once around the track in 380 s. What is the magnitude of the centripetal acceleration of the car?
*March 29, 2016*

**Physics**

Read the equation wrong, I got it. Sorry!
*March 29, 2016*

**Physics**

I know that Fc= mv^2r, and I keep getting r=.7154 but it says it's incorrect. What am I doing wrong? Help please!
*March 29, 2016*

**Physics**

At an amusement park there is a ride in which cylindrically shaped chambers spin around a central axis. People sit in seats facing the axis, their backs against the outer wall. At one instant the outer wall moves at a speed of 3.21 m/s, and an 75.7 kg person feels a 558 N ...
*March 29, 2016*

**chem**

Arrange the following compounds in order of increasing boiling point. butanal 1-butanol diethylamine tartaric acid butane butanoic acid and can you please explain why?
*March 28, 2016*

**Math**

Points J and K, plotted on the coordinate grid, are two vertices of rectangle JKLM. Rectangle JKLM has an area of 7 square units. Point J is located at (2, 1) and point K is located at (-5,1) each vertex of the rectangle is located at a point that has integer coordinates. Part...
*March 26, 2016*

**chemistry**

The formation constant* of [M(CN)4]2– is 7.70 × 1016, where M is a generic metal. A 0.170-mole quantity of M(NO3)2 is added to a liter of 1.040 M NaCN solution. What is the concentration of M2 ions at equilibrium?
*March 25, 2016*

**Physics**

Block B has a mass of 3.40kg and is moving to the left at a speed of 4.20m/s. Block A has a mass of 6.40kg and is moving to the right. The two blocks undergo a perfectly inelastic collision. What should the velocity of the Block A be in order to have the two blocks move to the...
*March 23, 2016*

**Physics**

Block B has a mass of 2.20kg and is moving to the left at a speed of 2.30m/s. Block A has a mass of 2.70kg and is moving to the right. The two blocks undergo a perfectly inelastic collision. What should be the velocity of Block A in order to have the two blocks remain at rest ...
*March 23, 2016*

**Math**

If adriana drew 20 pitchers and 3/4 of them are in art class how many pitchers did adriana draw in art class
*March 23, 2016*

**Physics**

A 63-kg ice-skater glides with a speed of 10 m/s toward a 14-kg sled at rest on the ice. The ice-skater reaches the sled and holds on to it. The ice-skater and the sled then continue sliding in the same direction in which the ice-skater was originally skating. What is the ...
*March 22, 2016*

**Physics**

A 64.8 kg ice skater is skating along in a straight line (in the positive direction) at 9.2 m/s when he bends down and scoops up his 24.4 kg doggy sitting still on the ice. What will be the new velocity of the dog-n-skater?
*March 22, 2016*

**Physics**

A car of mass 422 kg is moving 36.0° North of East at a speed of 15.4 m/s. What is the magnitude of the momentum of the car? (magnitude - how big is it? ignore direction). What is the east-west component of the momentum of the car? I already figured out the first question ...
*March 15, 2016*

**Physics**

A car of mass 422 kg is moving 36.0° North of East at a speed of 15.4 m/s. What is the magnitude of the momentum of the car? (magnitude - how big is it? ignore direction)
*March 15, 2016*

**Physics**

Suppose a 300–g kookaburra (a large kingfisher bird) picks up a 84.0–g snake and raises it 2.30 m from the ground to a branch. How much work did the bird do on the snake? I know that W=deltaPE, and PE=mgh. I keep getting 1046.64. Please help!
*March 10, 2016*

**calculus**

water is being siphoned from a cylindrical tank of radius 10m into a rectangular tank whose base measures 20m by 15m. if the depth of the water in the cylindrical tank in decreasing at a rate of 2m/s, at what rate is the depth of the water increasing in the rectangular tank
*March 10, 2016*

**Math**

Marco and his friends bought game tokens for $15 and three admission ticket. Determine if each statement below is true or false. If each admission ticket costs $2.50, then Marco and his friends spent $22.50 in all. True or False
*March 3, 2016*

**Math**

its D
*March 3, 2016*

**Algebra**

Two trains, one going from Boston to New York and the other going from New York to Boston, started their trips at exactly same time. Speed of the first train was 10 miles per hour less than twice the speed of the second train. How far from Boston station have they met, if the ...
*March 1, 2016*

**Physics**

3. A skater with an initial speed of 7.6 m/s is gliding across the ice. The coefficient of friction between the ice and the skae blades is μk=0.1. a. Find acceleration of the skater b. How foar will the skater travel before coming to rest
*February 29, 2016*

**Math**

Six year old Rosie wants to write down all counting numbers up to one thousand. When she finished writing 12, she had 15 digits. Rosie gave up after she had correctly written 2358 digits. What was the last number she wrote?
*February 27, 2016*

**Physics**

In the nail puller shown in the figure below you exert a force 49.6 cm from the pivot and the nail is 1.90 cm on the other side. What minimum force must you exert to apply a force of 1460 N to the nail to pull the nail up?
*February 26, 2016*

**Physics**

A 83.2-kg man stands on his toes by exerting an upward force through the Achilles tendon, as in the figure below. What is the force in the Achilles tendon if he stands on one foot?
*February 26, 2016*

**Physics**

Even when the head is held erect, as in the figure below, its center of mass is not directly over the principal point of support (the atlant-ooccipital joint). The muscles at the back of the neck should therefore exert a force to keep the head erect. That is why your head ...
*February 26, 2016*

**Physics**

What is the magnitude of the momentum of the 0.057-kg tennis ball when it travels at a speed of 29 m/s? Earth is the frame of reference.
*February 25, 2016*

**Physical science**

a balloon has a volume of 0.5 L at 20 degrees celsius. what will the volume be if the balloon heated to 150 degrees celsius? assume constant pressure and mass. I got 0.7218 L.
*February 21, 2016*

**Math**

A piece of ribbon is 7 1/2in. long. If a piece 2 3/16in. long is cut off, how long is the remaining piece?
*February 21, 2016*

**Physics**

Block A sits on a horizontal tabletop. There is friction between the surface and Block A. The string passes over a frictionless, massless pulley. Block B hangs down vertically. When the two blocks are released, Block B accelerates downward at a rate of 2.030 m/s2. What is the ...
*February 18, 2016*

**Physics**

The initial velocity of a 2.75 kg block sliding down a frictionless inclined plane is found to be 1.25 m/s. Then 1.05 s later, it has a velocity of 5.31 m/s. What is the angle of the plane with respect to the horizontal? I keep trying to use sine and cosine but I can't ...
*February 17, 2016*

**chemistry**

why are there only certain colours in an atomic emission spectra?
*February 16, 2016*

**Physics**

A 4.96 kg block located on a horizontal frictionless floor is pulled by a cord that exerts a force F=13.7N at an angle theta=16.0degrees above the horizontal. What is the magnitude of the acceleration of the block when the force is applied? I know a=F/m
*February 16, 2016*

**Physics**

Three blocks are located on a horizontal frictionless table. They are connected by a massless cord, as shown in the figure, and pulled to the right. The masses of the three blocks are m1 = 8 kg, m2 = 33 kg, and m3 = 49 kg. The pulling force is equal to T3 = 89 N. What is the ...
*February 16, 2016*

**Physics**

An elevator (cabin mass 600 kg) is designed for a maximum load of 2700 kg, and to reach a velocity of 3.4 m/s in 5 s. For this scenario, what is the tension the elevator rope has to withstand? I know I have to multiply the mass by the acceleration. I'm having a hard time ...
*February 16, 2016*

**chemistry**

Iron can be produced by the reduction of iron(III) Oxide by carbon monoxide: Fe2O3 + 3CO -> 2FE +3CO2 a) what maximum mass of CO2 could be produced from the complete reduction of 14.7g of Fe2O3? b) if 8.73g of CO2 gas was actually collected, what percentage yield of the ...
*February 15, 2016*

**Physics**

A block of weight 30.9 N is hanging from a rope. The tension from the rope is pulling upward on the block. The block is accelerating downward at a rate of 1.20 m/s2. What is the magnitude of the tension in the rope? I found the mass of the block to be 25.75 kg; however, I'...
*February 9, 2016*

**Physics**

A block of weight 30.9 N is hanging from a rope. The tension from the rope is pulling upward on the block. The block is accelerating downward at a rate of 1.20 m/s2. What is the magnitude of the tension in the rope?
*February 9, 2016*

**government**

Well, I think that we should abolish it because of the numerous scandals we've had and because I think it's not needed anymore but we're doing a debate on it and I was just wondering if there would be any other reasons that would help my case be stronger.
*February 9, 2016*

**government**

Should we abolish or reform the senate in Canada?
*February 9, 2016*

**pre-calculus**

x|x-3|<2 I did x(x-3)<2 or x(x-3)<2 and simplified it to x^2-3x<2 and am not sure how to simplify it further and express it in interval notation. Help!
*February 8, 2016*

**Physics**

We study the three point charges shown in the figure. They are held at the corners of an equilateral triangle with ℓ = 0.9 m. What is the electric potential energy of the system of three point charges? Use for the three charges q1 = +2Q, q2 = −3Q, and q3 = +Q, ...
*February 7, 2016*

**Physics**

A supertanker (mass = 1.90E+8 kg) is moving with a constant velocity. Its engines generate a forward thrust of 7.34E+5 N. Determine the magnitude of the resistive force exerted on the tanker by the water.
*February 4, 2016*

**Physics**

A 1550 kg car is traveling with a speed of 12.4 m/s. What is the magnitude of the horizontal net force that is required to bring the car to a halt in a distance of 50.3 m? I found the force of the car to be 14700 by using F=ma. I am confused on what to do with the rest of the ...
*February 4, 2016*

**Physics**

Three students converge on the last textbook in the store. All three grab it and begin to pull in the directions shown in the above figure. Student A exerts a force of 77.64 N, student B pulls with a force of 18.52 N, and student C pulls with a force of 66.43 N at an angle &#...
*February 4, 2016*

**Physics**

A force vector points at an angle of 50.8° above the +x axis. It has a y component of +282 newtons. Calculate the magnitude of the force vector.
*February 4, 2016*

**Physics**

A rocket is fired at a speed of 76.4 m/s from ground level, at an angle of 61.0° above the horizontal. The rocket is fired toward an 10.6 m high wall, which is located 26.2 m away. By how much does the rocket clear the top of the wall?
*February 4, 2016*

**science**

What is the relationship between the major body systems
*February 4, 2016*

**Physics**

A rock climber throws a small first aid kit to another climber who is higher up the mountain. The initial velocity of the kit is 10.1 m/s at an angle of 62.4° above the horizontal. At the instant when the kit is caught, it is traveling horizontally, so its vertical speed ...
*February 3, 2016*

**physics**

I don't understand. derive a general equation that will predict the horizontal range of a projectile that is fired from one vertical position and ends at any other vertical position with an initial velocity, V1, at an angle, pheta, from the horizontal. The equation should ...
*February 3, 2016*

**Math**

The question says to simplify it
*February 3, 2016*

**Math**

(5 root 3y) over (root10 + 2)
*February 3, 2016*

**Physics**

A block of weight 41.8 N is hanging from a rope. The tension in the rope is 24.4 N, pulling upward on the block. What is the magnitude and direction of the acceleration of the block? I know the direction would be downwards, since the tension of the rope is less than the weight...
*February 2, 2016*

**Pysics**

A block of weight 41.8 N is hanging from a rope. The tension in the rope is 24.4 N, pulling upward on the block. What is the magnitude and direction of the acceleration of the block? I know the direction would be downwards, since the tension of the rope is less than the weight...
*February 2, 2016*

**Physics**

A block of mass 4.11 kg is hanging from a rope. The tension in the rope is 23.5 N, pulling upward on the block. What is the magnitude and direction of the acceleration of the block? F=ma 23.5=4.11a The result was 5.72 and was not correct. Please help!
*February 2, 2016*