Wednesday

January 18, 2017
Total # Posts: 939

**physics**

A spring has a length of 0.190 m when a 0.300 kg mass hangs from it, and a length of 0.750 m when a 2.80 kg mass hangs from it. (a) What is the force constant of the spring? (b) What is the unloaded length of the spring?

*July 27, 2013*

**physics**

When 1.60 multiplied by 105 J of heat enters a cherry pie initially at 20.0°C, its entropy increases by 470 J/K. What is its final temperature (C)? Drwls answered: delta S = entropy change = 1.6*10^5*[1/293 - 1/T2] = 470 Solve for T2 But after I checked the answer, it is ...

*July 26, 2013*

**physics**

(a) How much heat (J) flows from 1.00 kg of water at 46.0°C when it is placed in contact with 1.00 kg of 18°C water in reaching equilibrium? (b) What is the change(J/K) in entropy due to this heat transfer? (c) How much work (J) is made unavailable, taking the lowest ...

*July 26, 2013*

**physics**

(a) What is the best coefficient of performance for a heat pump that has a hot reservoir temperature of 50.0°C and a cold reservoir temperature of -20.0°C? (b) How much heat in kilocalories would it pump into the warm environment if 3.60 multiplied by 107 J of work (10...

*July 26, 2013*

**physics**

While taking a plane flight to a meeting, a physicist decides to do a mental calculation of how much fuel the plane would consume in the absence of friction, assuming its engines have an efficiency of 22.0% and the mass of the plane is 200,000 kg. Each gallon of jet fuel ...

*July 26, 2013*

**physics**

Calculate the net work output of a heat engine following path ABCDA in Figure 14.30, where horizontal axis is V and each unit is 0.5*10^-3 m^3, V1 = 1.0*10^-3 m^3 and V2 = 4.0*10^-3 m^3. The vertical axis is P(N/m^2); A is (1.0*10^-3,2.6*10^6), B is (4.0*10^-3,2.0*10^6), C is...

*July 26, 2013*

**physics**

(a) How much heat (J) flows from 1.00 kg of water at 46.0°C when it is placed in contact with 1.00 kg of 18°C water in reaching equilibrium? (b) What is the change(J/K) in entropy due to this heat transfer? (c) How much work (J) is made unavailable, taking the lowest ...

*July 25, 2013*

**physics**

When 1.60 multiplied by 105 J of heat enters a cherry pie initially at 20.0°C, its entropy increases by 470 J/K. What is its final temperature (C)?

*July 25, 2013*

**physics**

(a) What is the best coefficient of performance for a heat pump that has a hot reservoir temperature of 50.0°C and a cold reservoir temperature of -20.0°C? (b) How much heat in kilocalories would it pump into the warm environment if 3.60 multiplied by 107 J of work (10...

*July 25, 2013*

**physics**

While taking a plane flight to a meeting, a physicist decides to do a mental calculation of how much fuel the plane would consume in the absence of friction, assuming its engines have an efficiency of 22.0% and the mass of the plane is 200,000 kg. Each gallon of jet fuel ...

*July 25, 2013*

**physics**

Calculate the net work output of a heat engine following path ABCDA in Figure 14.30, where horizontal axis is V and each unit is 0.5*10^-3 m^3, V1 = 1.0*10^-3 m^3 and V2 = 4.0*10^-3 m^3. The vertical axis is P(N/m^2); A is (1.0*10^-3,2.6*10^6), B is (4.0*10^-3,2.0*10^6), C is...

*July 25, 2013*

**physics**

(a) What is the magnitude of the average acceleration of a skier who, starting from rest, reaches a speed of 8.02 m/s when going down a slope for 4.28 s? (b) How far does the skier travel in this time?

*July 25, 2013*

**physics**

Concrete sidewalks are always laid in sections, with gaps between each section. For example, the drawing shows three identical 2.4-m sections, the outer two of which are against immovable walls. The two identical gaps between the sections are provided so that thermal expansion...

*July 25, 2013*

**physics**

An aluminum can is filled to the brim with a liquid. The can and the liquid are heated so their temperatures change by the same amount. The can’s initial volume at 8 °C is 4.8 × 10-4 m3. The coefficient of volume expansion for aluminum is 69 × 10-6 (C°...

*July 25, 2013*

**general physics**

When you take a bath, how many kilograms of hot water (40.8 °C) must you mix with cold water (11.3 °C) so that the temperature of the bath is 30.9 °C? The total mass of water (hot plus cold) is 190 kg. Ignore any heat flow between the water and its external ...

*July 25, 2013*

**physics**

I cant find it please specify

*July 17, 2013*

**physics**

A airplane is approaching you at a speed of 360km/h. If you measure the pitch of its approaching engines to be 512 Hz, what must be the actual frequency of the sound of the engines? The speed of sound in air is 345m/s answer is 364Hz please explain steps?

*July 17, 2013*

**solubility**

4.86*10^7 is correct. I also go it right on Sapling. x=2.09*10^-9 multiply by Molar Mass 234.605

*July 16, 2013*

**Physics**

The pressure exerted by a phonograph needle on a record is surprisingly large. If the equivalent of 1.00 g is supported by a needle, the tip of which is a circle 0.200 mm in radius, what pressure is exerted on the record in N/m2?

*July 14, 2013*

**Physics**

A straightforward method of finding the density of an object is to measure its mass and then measure its volume by submerging it in a graduated cylinder. What is the density of a 240-g rock that displaces 89.0 cm3 of water? (Note that the accuracy and practical applications of...

*July 14, 2013*

**Physics**

What is the final velocity of a hoop that rolls without slipping down a 5.00-m-high hill, starting from rest?

*July 14, 2013*

**Physics**

. (a) Calculate the angular momentum of an ice skater spinning at 6.00 rev/s given his moment of inertia is 0.400 kg ⋅ m2. (b) He reduces his rate of spin (his angular velocity) by extending his arms and increasing his moment of inertia. Find the value of his moment of ...

*July 14, 2013*

**Physics**

What is the moment of inertia of an object that rolls without slipping down a 2.00-m-high incline starting from rest, and has a final velocity of 6.00 m/s? Express the moment of inertia as a multiple of MR2, where M is the mass of the object and R is its radius.

*July 14, 2013*

**Physics**

Suppose you exert a force of 180 N tangential to a 0.280-m-radius 75.0-kg grindstone (a solid disk). (a)What torque is exerted? (b) What is the angular acceleration assuming negligible opposing friction? (c) What is the angular acceleration if there is an opposing frictional ...

*July 14, 2013*

**physics**

calculate the energy consumed by a computer(150 W) that is used for 2.0 hours and a laser(250 W) that is used for 10 min? Answer is 1.2 Mj

*July 10, 2013*

**physics**

A 54.5-kg passenger in the back seat of a van is wearing a seat belt when the van runs into a stone wall. The van is originally moving at 12.6 m/s. The front end of the van collapses 0.624 m as the van comes to rest. (a) Determine the passenger’s kinetic energy before the...

*July 10, 2013*

**Maths**

20sin55 is equal to 16.4 m

*July 10, 2013*

**physics**

A 0.662-kg basketball is dropped out of a window that is 6.32 m above the ground. The ball is caught by a person whose hands are 1.82 m above the ground. (a) How much work is done on the ball by its weight? What is the gravitational potential energy of the basketball, relative...

*July 8, 2013*

**physics**

A semi-trailer is coasting downhill along a mountain highway when its brakes fail. The driver pulls onto a runaway truck ramp that is inclined at an angle of 13.0° above the horizontal. The semi-trailer coasts to a stop after traveling 190 m along the ramp. What was the ...

*July 8, 2013*

**physics**

A pendulum bob swinging at a velocity of 10 m/sec would rise how high from its lowest point of its swing

*July 6, 2013*

**physical science**

A student, starting from rest, slides down a water slide. On the way down, a kinetic frictional force (a nonconservative force) acts on her. The student has a mass of 82 kg, and the height of the water slide is 11.3 m. If the kinetic frictional force does -6.2 × 103 J ...

*July 3, 2013*

**physics**

At a carnival, you can try to ring a bell by striking a target with a 11.6-kg hammer. In response, a 0.413-kg metal piece is sent upward toward the bell, which is 4.22 m above. Suppose that 26.2 percent of the hammer's kinetic energy is used to do the work of sending the ...

*July 3, 2013*

**Phys**

Starting from rest, a 1.6x10-4 kg flea springs straight upward. While the flea is pushing off from the ground, the ground exerts an average upward force of 0.38 N on it. This force does 2.6x10-4 J of work on the flea. (a) What is the flea's speed when it leaves the ground...

*July 3, 2013*

**physics**

A dynamite blast at a quarry launches a rock straight upward, and 2.2 s later it is rising at a rate of 17 m/s. Assuming air resistance has no effect on the rock, calculate its speed (a) at launch and (b)4.4 s after launch.

*July 2, 2013*

**Gen physics**

A 13,900 kg truck is moving at 23.5 m/s on a mountain road when the brakes are applied. The brakes FAIL!! Fortunately, the driver sees a deceleration (ouch!) ramp a short distance ahead. This is an incline used by out of control trucks to dissipate their KE by converting it to...

*July 1, 2013*

**physics**

A 34.1 kg child rides a Ferris wheel whose diameter is 18.3 m. When the ride is turning at a constant rate, the child’s speed has a constant value of 4.23 m/s. Find the normal force the seat exerts on the child at: a) The top of the ride b) The bottom of the ride

*July 1, 2013*

**Physics**

A 13,900 kg truck is moving at 23.5 m/s on a mountain road when the brakes are applied. The brakes FAIL!! Fortunately, the driver sees a deceleration (ouch!) ramp a short distance ahead. This is an incline used by out of control trucks to dissipate their KE by converting it to...

*July 1, 2013*

**general physics**

COMPLETELY STUCK? The period of rotation of the Moon is about 27 days, 8 hrs. The mass of the Moon is 7.35 x 1022 kg, and the radius of the Moon is 1.74 x 106 m. I wish to place a synchronous (period of orbit = period of the Moon’s rotation) satellite in orbit about the ...

*July 1, 2013*

**general physics**

His spacecraft, Vostok I, was a sphere about 2.3 m in diameter, and it reached a maximum altitude above Earth’s surface of 327 km. What was the spacecraft’s speed at this point in its orbit?

*July 1, 2013*

**physics**

starting from rest, find a 54.6kg child’s speed at the bottom of a 15.5m tall slide if it is assumed to be frictionless

*July 1, 2013*

**Physics**

1. a) Dy = Viy(t) + (1/2)(g)t^2 15.5 m = 0(t) + (1/2)(9.8 m/s^2)(t^2) t = sqrt[(15.5 m)/(4.9 m/s^2)] t = 1.8 sec answer b) Let V = speed of the ball just before it strikes the water. Vix = Vfx = 11.4 m/s Vfy = Viy + gt Vfy = 0 + (9.8 m/s^2)(1.8 s) Vfy = 17.64 m/s V = sqrt[Vfx^...

*June 18, 2013*

**Physics**

A golf ball rolls off a horizontal cliff with an initial speed of 12.2 m/s. The ball falls a vertical distance of 17.3 m into a lake below. (a) How much time does the ball spend in the air? (b) What is the speed v of the ball just before it strikes the water?

*June 18, 2013*

**Physics**

A meteoroid is speeding through the atmosphere, traveling east at 23.1 km/s while descending at 18.3 km/s. What is its speed, in km/s?

*June 18, 2013*

**Physics**

In a football game a kicker attempts a field goal. The ball remains in contact with the kicker's foot for 0.0475 s, during which time it experiences an acceleration of 417 m/s2. The ball is launched at an angle of 59.7° above the ground. Determine the (a) horizontal ...

*June 18, 2013*

**Physics**

A tennis ball is struck and departs from the racket horizontally with a speed of 27.3 m/s. The ball hits the court at a horizontal distance of 18.7 from the racket. How far above the court is the tennis ball when it leaves the racket?

*June 18, 2013*

**math**

vlad purchased some furniture for his apartment. The total cost was $2942.37. He paid $850 down and financed the rest for 18 months. At the end of the finance period. Vlad owed 2147.48. What annual interest rate compounded monthly eas he being charged? round your answers to ...

*June 10, 2013*

**chemistry**

How many liters of 20 Volume H2O2 will contain one mole of hydrogen peroxide?

*June 2, 2013*

**math**

Please help! :-)

*May 28, 2013*

**math**

108 ,36,12,4 ___ ,____find next two numbers 12,24 ,48,96 ____, ___ find the next two numbers 1 ,1,2,3 ____, ____ find the next two numbers

*May 28, 2013*

**math**

1.) Calculate the area of a circle with radius 8.5 inches. . 2.) Calculate the area of a circle with the diameter 15 feet. . 3.) Calculate the area of a circle with radius 9 feet

*May 19, 2013*

**science**

A science teacher tells her class that their final project requires the students to measure a specific variable and determine the velocity of a car with no more than 2.5% error. Jennifer and Johnny work hard and decide the velocity of the car is 34.87 m/s. The teacher informs ...

*May 19, 2013*

**math**

Oh ok Thank you

*May 15, 2013*

**math**

Would that be in inches

*May 15, 2013*

**math**

Draw and label a rectangle that has an area of 18 square units? . How much is that in width and length.

*May 15, 2013*

**calculus**

please anyone help me out Consider the following. Function Point f(x) = 5x^2 − 4, (3, 41) Find an equation of the tangent line to the function at the given point. y = Find the function values and the tangent line values at f(x + Δx) and y(x + Δx) for Δx...

*May 4, 2013*

**math calculus**

The concentration C (in milligrams per milliliter) of a drug in a patient's bloodstream t hours after injection into muscle tissue is modeled by C = 3t/26 + t^3 Use differentials to approximate the change in the concentration when t changes from t = 1 to t = 1.5. (Round ...

*May 4, 2013*

**math calculus**

hey bobpursley i tried this one on my own but i don't get the right answer i mean if u can give me the solution i will look at it thanks

*May 4, 2013*

**Algebra**

Hearst Castle is 180 miles from Ventura by road. Two coaches leave Ventura at the same time, both heading for Hearst Castle, but one averages 5 mph faster than the other. If the faster coach reaches Hearst Castle half an hour earlier than the slower coach, what is the average ...

*April 28, 2013*

**math**

What am I? I have four digits is 1. The product of my digits is 0

*April 22, 2013*

**geomtry**

find the arc length of the minor arc withe degree of 120 and a radius of 8

*April 18, 2013*

**Algebra.. PLEASE help me!!**

e=mc2

*April 11, 2013*

**LA**

i think its B or C

*April 11, 2013*

**LA**

How did the Civil War affect the Northern and Southern economies? A;The North experienced more severe inflation than the South. B;Overall the South fared much worse economically than the North. C;The South experienced a boom in manufacturing. D;The North's economy was ...

*April 11, 2013*

**LA**

How did the Civil War affect the Northern and Southern economies? A;bounties B;greenbacks C;draft D;habeas corpus

*April 11, 2013*

**Algebra**

A theater company's annual profit is modeled by the equation P= 0.2x^2-6.8x, where x is the number of plays performed in a year. How many plays must the company present in order to make a profit?

*March 28, 2013*

**Algebra**

Mr. Jones estimate his profit starting in 2006 will be given by the formula P=7t^2-14t+10 where t is number of years and P is the profit. If this formula is correct, when will Mr. Jones have a profit of more than $1000.00?

*March 28, 2013*

**statistics**

two spot available and there is 6 men and 4 women what is the probability that a women will be picked?

*March 22, 2013*

**US History**

can somebody answer it

*March 1, 2013*

**physics**

Two point charges totaling 9.00 µC exert a repulsive force of 0.300 N on one another when separated by 0.596 m. (A) What is the charge on each? (B) What is the charge on each if the force is attractive? smallest charg

*February 28, 2013*

**Information Systems**

Problem #2 from page 173 Given the following business scenario, create a Crow’s Foot ERD using a specialization hierarchy if appropriate. Tiny Hospital keeps information on patients and hospital rooms. The system assigns each patient a patient ID number. In addition, the ...

*February 25, 2013*

**pre-algrebra**

What is the missing coefficient x 2 4x -2x x 2 ______ x

*February 19, 2013*

**Math**

Serena paid $20.20 for 36 rulers and folders. She bought 16 more folders than rulers. If each folder cost $0.50 more than each ruler, how much did each folder cost?

*February 14, 2013*

**Math**

"One leg of a right triangle is 50.A line parallel to the other leg and at a distance of 20 from that leg cuts off a right trapezoid of area 320. What is the area of the original right triangle?"

*February 13, 2013*

**math**

41<x<52

*February 13, 2013*

**Math**

720

*February 9, 2013*

**Criminal precedure**

y answers 1.a 2a 3.d 4.d 5.a 6.a 7.b 8.b 9.c 10.b 11.c 12.a 13.d 14.b 15.c 16.c 17.c 18.a 19.b 20.b

*February 5, 2013*

**Criminal precedure**

Yea i am i m just really struggling on this test and can use some ones help?

*February 5, 2013*

**Criminal precedure**

Question 11 of 20 5.0 Points Under the Fourth Amendment, which of the following is NOT a valid purpose for setting up a roadblock? A. Immigration law enforcement B. Detecting drunk drivers C. Checking for drivers licenses and registration D. Drug detection Reset Selection ...

*February 5, 2013*

**Physics**

webassign(.)net/yf/22-30.gif The image above shows some of electric field lines due to 3 poin charges along the vertical axis. All 3 charges have the same magnitude. A. What are the signs of the 3 charges? Explain reasoning. B. At what points is the magnitude of the electric ...

*February 2, 2013*

**Chemistry**

How many molecules are there in 24 grams of FeF3 ? Can somebody please show me how i can get to the answer ? Thank you

*January 30, 2013*

**Physics**

This is not correct. The answer is simply as follows: Let f* be the fundamental frequency. Then f*[(1/4)-(1/7)]=144Hz. f* = 1344 Hz

*January 30, 2013*

**math**

The number of Roberto's baseball cards is 3/4 the number of David's cards. If Roberto gives 1/2 of his cards to David, what will be the ratio of Roberto's cards to David's cards?

*January 28, 2013*

**algebra**

If a car goes 0-85mph in 500' How many seconds does it take to get there?

*January 24, 2013*

**Math**

Roger knows how many keys a piano has. He knows that some of the keys are broken. How can he find the number of keys that work?

*January 23, 2013*

**Math**

a mother wants to invest 5000 for her sons future education. She invests a portion of the money in a bank certificate of deposit which earns 4% and the remainder in a savings bond that earns 7%. If the total interest earned after one year is $300.00,how much money was invested...

*January 20, 2013*

**Math**

A bowling ball is dropped from a bridge, and it takes 7 seconds to hit the ground. How far did the bowling ball fall?

*January 20, 2013*

**Math**

2x^3-x^2-6x / 2x^2-7x+6

*January 13, 2013*

**Math**

Please factor 2x^2-xy-y^2 Briefly explain steps

*January 13, 2013*

**Math**

X^4y^3-x^2y5

*January 10, 2013*

**math**

In Samuel's sports memorabilia collection there are 27 hockey items, 36 baseball items, and 29 football items. Which pair of item classifications (hockey, baseball, football) exists in the largest ratio?

*January 9, 2013*

**geometry**

Suppose the coordinate of p=2 and PQ=8 and PR=12. Whare are the possible mid point for line segment PQ? A.-2 &8 B. 2 & 6 C.-2 & 6 D.-2

*January 8, 2013*

**Physics**

200/1.5=133

*January 4, 2013*

**art**

Compare and contrast the modern day art of David smith "cubi series" with that of stonehedge in regards to the elements of art.

*December 30, 2012*

**Can anyone please help me this biology please !!!**

Thanks for your help

*December 13, 2012*

**Can anyone please help me this biology please !!!**

I am really stuck in this biology it super hard how do yeast cells benefit from fermentation ?I wil be happy if anyone would help me out thanks.

*December 13, 2012*

**Physics**

What is the gravitational force between two runners standing 100 meters apart on a track, if their masses are 60 kg and 75 kg respectively?

*December 6, 2012*

**chemistry**

copper (II) flourine comtains 37.42 % of mass. use this percentage to calculate the mass of flourine in grams contained in 28.5 g of copper (II) flourine

*December 5, 2012*

**math**

convert 50 miles per hour in feetvper second(round to the nearest whole.)

*December 4, 2012*

**math**

A jet plane traveling at 500 mph overtakes a propeller plane traveling at 200 mph that had a 2-hour head start. How far from the starting point are the plains?

*December 4, 2012*

**math**

Supppose two trains leave Holbrook, Arizona, at the same time, traveling in opposite directions. One train travels 10 mph faster than the other. In 3.5 hours, the trains are 322 miles apart. Find the speed of each train.

*December 4, 2012*