Tuesday

February 28, 2017
Total # Posts: 2,426

**science**

A shoe case weighing 40 lb is located on a scale inside a moving elevator that is going upward with the speed of 8 m/s. At time T1 elevator slows down with the acceleration of 3 m/s2 until the time T2. What are the the readings of the scale at T2 and T1 respectively?

*July 25, 2012*

**chemistry**

When do phase transitions occur in molecules?

*July 25, 2012*

**Physics**

I tried using a method similar to yours earlier, but I got around 70 to 80 degrees C when using it, so I tried another method. I get the same answer of 24.6C when using my method, so I'm confused as to why you don't like it. Also, when I use the specific heat of mild ...

*July 24, 2012*

**Physics**

The answer is supposed to be 27 degrees C; however, I keep getting 25 degrees C. Could someone check my method? m(w)c(w)T(iw) + m(s)c(s)T(is) = m(w)c(w)T(f) + m(s)c(s)T(f) where m(w) is the mass of the water, c(w) is the specific heat of water in cal/(g K), m(s) is the mass of...

*July 24, 2012*

**Physics**

A 2.0-kg piece of steel with a temperature of 70°C is submerged in 1.0 kg of water at 15°C. At what temperature does the water/metal system reach equilibrium? The specific heat of steel is 0.107 cal/(g × K)."

*July 24, 2012*

**Physics**

Which one of the following will form a standing wave: (1) two waves of the same amplitude and speed moving in the same direction (2) two waves of the same amplitude and speed moving in the opposite directions, (3) any two traveling waves can form standing wave if they have ...

*July 24, 2012*

**Physics**

Two cylindrical rods are made of the same material and have the same length but one is hollow and other is solid. Both are heated to same increase in temperature. Which rod expands more? From my understanding of linear thermal expansion, linear thermal expansion only depends ...

*July 23, 2012*

**cis 324**

You are an information security manager for a large retail sporting goods store. The sporting goods store is involved in the following in which they: •Maintain an internal network and an intranet protected by a firewall •Maintain a Web server in the DMZ that is ...

*July 23, 2012*

**Physics**

The table gives the specific heat of lead as 0.129 KJ/(kgK) and 0.0308 cal/(gK).

*July 19, 2012*

**Physics**

I tried using: .7E = 1/2mv^2 - cm(dT) However, I do not know the total energy of the system, so I can't finish the problem this way.

*July 19, 2012*

**Physics**

A 19-g lead bullet is shot with a speed of 340 m/s into a wooden wall. Assuming that 70% of the kinetic energy is absorbed by the bullet as heat (and 30% by the wall), what is the final temperature of the bullet? (Assume the bullet is initially at room temperature of 20°C...

*July 19, 2012*

**Physics**

I forgot that 70g was 0.07 kg. I was using 0.007 kg. Thank you. This question makes a lot more sense now.

*July 19, 2012*

**Physics**

I'm getting -25.1 g when I use this equation.

*July 19, 2012*

**Physics**

Suppose 100 g of water at 20°C is poured over a 70-g cube of ice with a temperature of -8°C. If all the ice melts, what is the final temperature of the water? If all of the ice does not melt, how much ice remains when the water–ice mixture reaches equilibrium? I&#...

*July 19, 2012*

**Physics**

The equation I found in my text book doesn't mention time being a factor when calculating R. I have R= L/k where L is length and k is thermal conductivity.

*July 19, 2012*

**Physics**

Thank you! Could you write out just the basic equation that you used?

*July 19, 2012*

**Physics**

The thermal conductivity of fiberglass batting, which is 8.9 in thick, is 8.6 10-6 BTU/(ft °F s). What is the R value (in ft2 °F h/BTU)? The R value is 24 ft^2 Fh/BTU. How do I get this answer?

*July 19, 2012*

**Physics**

A comet orbits the Sun with a period of 72.0 yr. (a) Find the semimajor axis of the orbit of the comet in astronomical units (1 AU is equal to the semimajor axis of the Earth's orbit). (b) If the comet is 0.60 AU from the Sun at perihelion, what is its maximum distance ...

*July 18, 2012*

**Calculus**

The Estradas are planning to buy a house 5 years from now. Housing experts in their area have estimated that the cost of a home will increase at a rate of 3%/year during that 5-year period. If this economic prediction holds true, how much can the Estradas expect to pay for a ...

*July 15, 2012*

**Physics**

I see where my mistake was. I multiplied in the pi when I wasn't supposed to. This question had an obvious answer.

*July 13, 2012*

**Physics**

Any help is appreciated.

*July 13, 2012*

**Physics**

A sinusoidal wave traveling on a string is moving in the positive x-direction. The wave has a wavelength of 6 m, a frequency of 48 Hz, and an amplitude of 9 cm. What is the wave function for this wave? (Use any variable or symbol stated above as necessary.) I know the answer ...

*July 13, 2012*

**Physics**

Thank you! I was able to figure out the correct answer. However, in this case shouldn't (.011^2) be (.011/2)^2?

*July 13, 2012*

**Physics**

The tension in a 2.6-m-long, 1.1-cm-diameter steel cable (ρ = 7800 kg/m3) is 860 N. What is the fundamental frequency of vibration of the cable? The answer is 6.55 Hz. I know that I'm going to use the formula: f=nsqrt(T/4L^2u) However, I'm not sure how to get the ...

*July 13, 2012*

**Physics**

Also, shouldn't f=48.9 m be f=48.9 Hz?

*July 12, 2012*

**Physics**

Thank you. I guess WebAssign made a mistake.

*July 12, 2012*

**Physics**

I'm not really sure how to figure out part (b); however, I'm sure that it's answer relies on me figure out part (a) correctly.

*July 12, 2012*

**Physics**

For part (a) I've been doing the following work: u=M/L; where u= mass per unit length u=(0.011)/(.48)= 0.022916667 v= sqrt(T/u); where T = tension v= sqrt(50.5/0.022916667) = 47.0 m/s

*July 12, 2012*

**Physics**

A 48-cm-long wire with a mass of 11.0 g is under a tension of 50.5 N. Both ends of the wire are held rigidly while it is plucked. (a) What is the speed of the waves on the wire? (b) What is the fundamental frequency of the standing wave? The answers are 50.5 m/s and 48.9 Hz ...

*July 12, 2012*

**Physics**

A string is 37.5 cm long and has a mass per unit length of 5.95 10-4 kg/m. What tension must be applied to the string so that it vibrates at the fundamental frequency of 612 Hz? The answer is supposed to be 125 N, but I'm not sure how to get this answer. So far, I have ...

*July 12, 2012*

**distance 2 cars**

if car A is going 40 mph and car B is stationary , how fast would car b have to go to cath up to car A in 4/10 of a mile

*July 11, 2012*

**Physics**

A 3-kg mass attached to a spring with k = 145 N/m is oscillating in a vat of oil, which damps the oscillations. (a) If the damping constant of the oil is b = 14 kg/s, how long will it take the amplitude of the oscillations to decrease to 1% of its original value? (b) What ...

*July 9, 2012*

**Stats**

In a study of children with a particular disorder, parents were asked to rate their child on a variety of items related to how well their child performs different tasks. One item was "Has difficulty organizing work," rated on a five-point scale of 0 to 4 with 0 ...

*July 9, 2012*

**Stats**

Thank you!

*July 9, 2012*

**Stats**

You want to rent an unfurnished one-bedroom apartment in Boston next year. The mean monthly rent for a random sample of 14 apartments advertised in the local newspaper is $1200. Assume that the standard deviation is $230. Find a 95% confidence interval for the mean monthly ...

*July 9, 2012*

**Probability & Statistics**

You want to rent an unfurnished one-bedroom apartment in Boston next year. The mean monthly rent for a random sample of 14 apartments advertised in the local newspaper is $1200. Assume that the standard deviation is $230. Find a 95% confidence interval for the mean monthly ...

*July 9, 2012*

**Physics**

One of the related questions helped me. Thank you Jiskha!

*July 7, 2012*

**Physics**

When a mass is attached to a vertical spring, the spring is stretched a distance d. The mass is then pulled down from this position and released. It undergoes 53 oscillations in 30.6 s. What was the distance d? The answer is supposed to be 8.28 cm. How can I get this answer? ...

*July 7, 2012*

**physics**

Suppose a cars brakes can produce an acceleration of -7m/s^2. If the car is traveling at an initial speed of 28m/s, what is the minimum distance necessary to stop the car?

*July 7, 2012*

**Economics**

I believe the answer is A

*July 6, 2012*

**Algebra**

At what time between 7 and 8 on an analog clock do the hour and minute hand overlap?

*July 4, 2012*

**Physics**

Thank you! By the way, using 101325 instead of 1.01e+05 and using pi instead of 3.14 gives a more accurate answer. Using these values gives me 80425.39066 N, which rounds down to 80400 N.

*July 2, 2012*

**Physics**

I have tried to follow the similar problem under the "related questions", but I get 5.29e+6 N from doing it this way.

*July 2, 2012*

**Physics**

In a hydraulic lift, the maximum gauge pressure is 16.70 atm. If the diameter of the output line is 24.6 cm, what is the heaviest vehicle that can be lifted? The answer is 80400 N. How do I get this answer? Isn't weight measured in kg? Thank you in advance.

*July 2, 2012*

**Physics**

A wooden block floating in seawater has two thirds of its volume submerged. When the block is placed in mineral oil, 10% of its volume is submerged. ( a) Find the density of the wooden block. (The density of seawater is 1.024 g/cm3.) (b) Find the density of the mineral oil.

*July 2, 2012*

**Math**

p=80000, r=10.5, t=15, m=12

*July 1, 2012*

**Physics**

A comet orbits the Sun with a period of 72.0 yr. (a) Find the semimajor axis of the orbit of the comet in astronomical units (1 AU is equal to the semimajor axis of the Earth's orbit). (b) If the comet is 0.60 AU from the Sun at perihelion, what is its maximum distance ...

*June 30, 2012*

**Physics**

Eris, the largest dwarf planet known in the Solar System, has a radius R = 1200 km and an acceleration due to gravity on its surface of magnitude g = 0.77 m/s2. (a) Use these numbers to calculate the escape speed from the surface of Eris. (b) If an object is fired directly ...

*June 29, 2012*

**Writing/BME**

I meant to say "The material's tolerance to stress..." not "The material tolerance."

*June 28, 2012*

**Writing/BME**

As strength is defined as the amount of stress a material can withstand before fracturing, the material used to construct a toric lens should have a relatively high tolerance to stress. The material tolerance to stress should be relatively high when facing each type of stress...

*June 28, 2012*

**Writing/BME**

Strength is defined as the amount of stress a material can withstand before fracturing. Therefore, the more strength a material has, the more durable it is. Thus, a toric lens should be constructed from a material with high strength. Every time I read this to myself, it sounds...

*June 28, 2012*

**Physics**

I'm getting a negative answer when I checked your math. Also, shouldn't the mass of the rock be considered?

*June 28, 2012*

**Physics**

Standing on the surface of a small spherical moon whose radius is 6.30 104 m and whose mass is 8.00 1018 kg, an astronaut throws a rock of mass 2.02 kg straight upward with an initial speed 42.2 m/s. (This moon is too small to have an atmosphere.) What maximum height above the...

*June 28, 2012*

**statistics**

A firm has 30% of its service calls made by a contractor, and 15% of these calls result in customer complaints. The other 70% of the service calls are made by their own employees, and these calls have a 5% complaint rate. Use Bayes’ theorem to find the probability that a ...

*June 27, 2012*

**statistics**

In a statistic class, 10 scores were randomly selected with the following results were obtained: 74, 73, 87, 57, 71, 68, 65, 77, 67, 66. What are the inner fences? What is the coefficient of variation?

*June 27, 2012*

**Physics**

Suppose a new extrasolar planet is discovered. Its mass is double the mass of the Earth, but it has the same density and spherical shape as the Earth. How would the weight of an object at the new planet's surface differ from its weight on Earth? (Let Wnew be the weight of ...

*June 26, 2012*

**Physics**

A ladder of mass 39.4 kg and length 2.88 m is leaning against a wall at an angle θ. The coefficient of static friction between ladder and floor is 0.282; assume that the friction force between ladder and wall is zero. What is the maximum value that θ can have before ...

*June 25, 2012*

**business finance**

Hot Wings, Inc., has an odd dividend policy. The company has just paid a dividend of $11.25 per share and has announced that it will increase the dividend by $9.25 per share for each of the next four years, and then never pay another dividend. Required: If you require a 13 ...

*June 25, 2012*

**physics**

Now I'm getting over 1000. However, I may be reading your explanation wrong. I'll reread your explanation again.

*June 22, 2012*

**Physics**

Thank you for the help. I managed to get the correct solution.

*June 22, 2012*

**Physics**

I forgot about the negative. Thank you!

*June 22, 2012*

**Physics**

The quadratic equation is not really working. I keep getting imaginary numbers from the negative under the radical.

*June 22, 2012*

**Physics**

Thank you. I completely forgot about the quadratic formula.

*June 22, 2012*

**Physics**

A track has a height that is a function of horizontal position x, given by h(x) = x^3 + 4x^2 − 44x + 16. Find all the positions on the track where a marble will remain where it is placed. What kind of equilibrium exists at each of these positions? (Enter your answers ...

*June 22, 2012*

**Physics**

Thank you so much! I've been trying to figure this one out for a few hours.

*June 21, 2012*

**Physics**

A uniform rigid pole of length L and mass M is to be supported from a vertical wall in a horizontal position, as shown in the figure. The pole is not attached directly to the wall, so the coefficient of static friction, μs,between the wall and the pole provides the only ...

*June 21, 2012*

**Medical coding**

Which of the following is true about the ICD-10-CM? A. An eighth character was added. B. There are combination diagnosis/symptom codes. C. There are limited injury codes. D. There's additional information relevant to inpatient encounters. unsure of answer? What category ...

*June 20, 2012*

**Physics**

The system shown in the figure is held initially at rest. Calculate the angular acceleration of the system as soon as it is released. You can treat MA (1 kg) and MB (12 kg) as point masses located on either end of the rod of mass MC (27 kg) and length L (9 m). (Indicate the ...

*June 20, 2012*

**Medical coding**

yes I am so sorry.

*June 19, 2012*

**penn foster**

A cause-and-effect relationship must be stated or evident in order to code which of the following? A. Sequence B. Hypertensive condition C. Atherosclerosis D. Manifestation unsure of answer? 16. Which of the following is true about the ICD-10-CM? A. An eighth character was ...

*June 19, 2012*

**Physics**

Actually since it's shot vertically upwards, the angle should be 90 degrees. I was able to figure this question out. Thank you for trying to help.

*June 19, 2012*

**Physics**

It's not given.

*June 19, 2012*

**Physics**

A small circular object with mass m and radius r has a moment of inertia given by I = cmr^2. The object rolls without slipping along the track shown in the figure. The track ends with a ramp of height R = 3.0 m that launches the object vertically. The object starts from a ...

*June 19, 2012*

**Physics**

A force, F = (3x + 4y) N, is applied to an object at a point whose position vector with respect to the pivot point is r = (3x + 3y + 3z) m. Calculate the torque created by the force about that pivot point. I know that torque = -12x + 9y + 3z, but why is -12x negative? Thank ...

*June 18, 2012*

**Physics**

A solid ball and a hollow ball, each with a mass of 2 kg and radius of 0.1 m, start from rest and roll down a ramp of length 2 m at an incline of 34°. An ice cube of the same mass slides without friction down the same ramp. What is the speed of the solid ball at the bottom...

*June 18, 2012*

**Physics**

10. A yo-yo is made by wrapping a 2-m long string around a 500-g 10-cm diameter uniform disk. The string is fastened to the ceiling, and the yo-yo is released. What is the tension in the string as the yo-yo falls? A.9.8N B.1.6N C.4.9N D. 0.49N E.3.3N The answer is B. How do I ...

*June 17, 2012*

**math**

75 is 5/2 of greg's age

*June 17, 2012*

**help**

Post those question you are having trouble with on this site and one of the tutors should answer your question.

*June 16, 2012*

**Physics**

How is it known that the mass of the cutout is centered at (2/3)R?

*June 16, 2012*

**Physics**

5. A circular pizza of radius R has a circular piece of radius R/3 removed from one side. The center of mass of the pizza with the hole is at a distance of_____ from the center of mass of the original pizza. A. R/20 B. R/2 C. R/30 D. R/3 E. R/12 The answer is E, but why is it ...

*June 16, 2012*

**Physics**

Thank you.

*June 16, 2012*

**Physics**

A ball of mass m = 0.2 kg is attached to a (massless) string of length L = 2 m and is undergoing circular motion in the horizontal plane (imagine a wave swinger ride at the amusement park). What should the speed of the mass be for θ to be 39°? What is the tension in ...

*June 16, 2012*

**Physics**

A ball having a mass of 4 kg is attached to a string 1 m long and is whirled in a vertical circle at a constant speed of 23 m/s. (a) Determine the tension in the string when the ball is at the top of the circle. (b) Determine the tension in the string when the ball is at the ...

*June 14, 2012*

**math**

How many cement blocks are needed to construct a wall 0.5 ft. thick, 6 ft. high, and 60 ft. long if it takes 10 standard cement blocks to make 1 cubic foot of wall?

*June 14, 2012*

**math**

A pile of coal is stored in a barrel-shaped bin whose base has a radius of 3 meters. The height of the pile measures 1.5 meters. What volume of coal is in the pile (to the nearest hundredth)?

*June 14, 2012*

**Math**

You are to paint the globe held aloft by a statue of Atlas. Its diameter is 10.5 in. How much surface area must you cover with paint if 27 square inches does not need to be painted (to the nearest hundredth)?

*June 14, 2012*

**Physics**

A discus thrower (with arm length of 1.2 m) starts from rest and begins to rotate counterclockwise with an angular acceleration of 3.6 rad/s2. (a) How long does it take the discus thrower's speed to get to 5.1 rad/s? (b) How many revolutions does the thrower make to reach ...

*June 14, 2012*

**Physics**

Thank you.

*June 14, 2012*

**Physics**

1. A slingshot is used to launch a 5.00-gram rock. The effective spring constant of the slingshot is 200 N/m. By what distance must the slingshot be stretched in order to launch the rock at 20.0 m/s?

*June 14, 2012*

**early childhood**

When children learning. Alphabet which do they recognize first. A.oc B.kc C.br D.te

*June 12, 2012*

**Physics**

A system consists of two particles. Particle 1 with mass 2.0 kg is located at (2.0 m, 6.0 m) and has a velocity of (2.1 m/s, 4.1 m/s). Particle 2 with mass 4.5 kg is located at (4.0 m, 1.0 m) and has a velocity of (4.6 m/s, 4.6 m/s). Determine the position and the velocity of ...

*June 12, 2012*

**Physics**

The density of a 5.0-m long rod can be described by the linear density function λ(x) = 140 g/m + 14.8x g/m2. One end of the rod is positioned at x = 0 and the other at x = 5 m. (a) Determine the total mass of the rod. (b) Determine the center-of-mass coordinate. I found ...

*June 11, 2012*

**Physics**

A fire hose 3.8 cm in diameter is capable of spraying water at a velocity of 20 m/s. For a continuous horizontal flow of water, what horizontal force should a fireman exert on the hose to keep it stationary? I know the answer is 454 N but how does one arrive at this answer?

*June 11, 2012*

**Managerial Accounting**

What is FedEx’s strategy for success in the marketplace? Does the company rely primarily on a customer intimacy, operations excellence, or product leadership customer value proposition? What evidence supports your conclusion? What are FedEx’s four main business ...

*June 10, 2012*

**physics**

A motor drives a rope drum of 820 mm diameter, which in turn drags a component of mass 650 kg, 175 m up a slope that makes an angle of 8 degrees to the horizontal. the component starts from rest and uniformly reaches a velocity of 5.3 m/s on completion of its journey. use d&#...

*June 7, 2012*

**English 125 Introduction to literature**

The performance qualities of drama and poetry

*June 6, 2012*

**Physics**

A 0.421-kg ball has an elastic, head-on collision with a second ball that is initially at rest. The second ball moves off with half the original speed of the first ball. (a) What is the mass of the second ball? (b) What fraction of the original kinetic energy (ΔK/K) is ...

*June 6, 2012*

**Physics**

I think my book has a typo. It should say book, not ball.

*June 5, 2012*

**Physics**

Stuck in the middle of a frozen pond with only your physics book, you decide to put physics in action and throw the 9-kg book. If your mass is 45 kg and you throw the book at 10 m/s, how fast do you then slide across the ice? (Assume the absence of friction. Let the direction ...

*June 5, 2012*

**Science/Biomaterials**

Hooke's law relates the amount of strain a material to the absolute amount of force applied. True or False?

*June 5, 2012*