# physics-bobpursley/drwls

74,029 results

### physics-bobpursley/drwls please check

bobpursley/ drwls please help me with my post on Sunday, April 15 at 10:16pm and 10:19pm. Thanks!

### Physics

A vertical spring with a spring constant of 450 N/m is mounted on the floor. From directly above the spring, which is unstrained, a 0.30 kg block is dropped from rest. It collides with and sticks to the spring, which is compressed by 3.0 cm in bringing the block to a momentary...

### Physica

Peace, and mercy and blessings of God Atqm thank you for helping me teach my children and success in physics at the Mah their college education and that the wrinkles in the balance Hassanatkm for all and especially Damo,Drwls, bobpursley.Elena

### physics-bobpursley/drwls

Good morning! I just wanted to say thank you for all of your help. This was my first time taking Physics ever and it was like a foreign language to me. For a long time during this semester I had an "F" average, because of you both I have passed my physics class with a "C". ...

### algebra 2

Posted by hellogoodbie on Saturday, January 16, 2010 at 3:24pm. Posted by hellogoodbie on Saturday, January 16, 2010 at 2:59pm. How is this problem done? IF f(x)=2x^2-8x-3 FIND f(-2) algebra 2 - bobpursley, Saturday, January 16, 2010 at 1:42pm Put in for x the value -2, and ...

### Physics- drwls please check

Good morning. This is a repost. The system is telling me my calculations is incorrect. I thought a fresh pair of eyes would help. Suppose a monatomic ideal gas is contained within a vertical cylinder that is fitted with a movable piston. The piston is frictionless and has a ...

### algebra 2

Posted by hellogoodbie on Saturday, January 16, 2010 at 2:59pm. How is this problem done? IF f(x)=2x^2-8x-3 FIND f(-2) algebra 2 - bobpursley, Saturday, January 16, 2010 at 1:42pm Put in for x the value -2, and compute f(-2) algebra 2 - hellogoodbie, Saturday, January 16, 2010...

### physics: drwls

drwls for the question below, the answer seems to be wrong: The four tires of an automobile are inflated to a gauge pressure of 1.8 multiplied by 105 Pa. Each tire has an area of 0.025 m2 in contact with the ground. Determine the weight of the automobile. It asks for the ...

### music yr 8- re- drwls

thankyou drwls for your help on buddy holly

### physics - another question

Sam is sitting in her fishing boat watching a trout swim below the surface. She guesses the apparent depth of the trout at 2.0m. She estimates that her eyes are about 1.0 m above the water's surface, and that the angle at which she's observing the trout is 45 degrees. b) ...

### Physics to bobpursley or any1 else who knows this

A planet has two satellite moons. Moon X has an orbital period of 2.13 days. Moon Y has an orbital period of about 3.53 days. Both moons have nearly circular orbits. Use Kepler's third law to find the distance of each satellite from the planet's center. The planet's mass is 2....

### Physics check

A speeder traveling at 41 m/s passes a motorcycle policeman at rest at the side of the road. The policeman accelerates at 3.3 m/s2. To the nearest tenth of a second how long does it take the policeman to catch the speeder? Im sorry I am new to physics this is my first year and...

### Physics-bobpursley or drwls please check if possib

If I had the old-fashion camera that had a focal length of 35mm(0.035m) and I take a picture of a person 6 m away, how far does the film need to be from the lens to record a clear image? I know that the equation is 1/f = 1/d(object) + 1/d(image) so would I do the following: 1/...

### trigonometry

Find the distance using the appropriate arch length. A television tower 520m high subtends an angle of 2deg30'. How far away is the tower? some people that helped me alot were Reiny, Damon, bobpursley, and drwls..so i just wanna say thnks to you guys...are u guys math expersts...

### DrRuss/bobpursley/drwls please help!!!

Can you please clarify your response to my post Wednesday April 4th at 8:53pm and 8:54pm. Thanks for all of your help!!! pleasde repost it. Yes, repost it. Go to it, copy, and paste it here. Thanks. A vertical spring with a spring constant of 450 N/m is mounted on the floor. ...

### math

Posted by mota THE MASS OF THE SUN IS ABOUT 10^27 METRIC TONS , OR 10^30 KILOGRAMS . HOW MANY KILOGRAMS ARE IN ONE METRIC TON ? ----------------------- math - drwls 1000. ----------------------- explain please i want to understand this question :) this is my question i posted ...

### physics

Posted by sandhu on Tuesday, November 30, 2010 at 1:17am. A T is made of two identical 740 g thin solid rods. The moment of inertia of the T about an axis perpendicular to the screen through point at one end of a rod is determined experimentally to be 0.68 kg-m2. What is the ...

### Physics

Two 0.09g pith balls are suspended from the same point by threads 40cm long. (Pith is a light insulating material once used to make helmets worn in tropical climates.) When the balls are given equal charges, they come to rest 19 cm apart What is the magnitude of the charge on ...

### physics

Posted by sandhu on Tuesday, November 30, 2010 at 7:38pm. Posted by sandhu on Tuesday, November 30, 2010 at 1:17am. A T is made of two identical 740 g thin solid rods. The moment of inertia of the T about an axis perpendicular to the screen through point at one end of a rod is...

### Damon or Steve or bobpursley or drwls or ...

any ideas ? , looks way too messy for here http://www.jiskha.com/display.cgi?id=1361092708

### physics repost bobpursley

The energy given off by 300 grams of an alloy as it cools through 50°C raises the temperature of 300 grams of water from 30°C to 40°C. The specific heat of the alloy (in cal/g C ) is: i know Q=CpM(delta T) but what is what? Responses * physics - bobpursley, Monday, June 22...

### physics

An athlete at the gym holds a 4.33 kg steel ball in his hand. His arm is 75.0 cm long and has a mass of 5.28 kg. What is the magnitude of the torque about his shoulder if he holds his arm straight out to his side, parallel to the floor? Responses Physics - bobpursley, Saturday...

### physics

thank you for your help drwls

### math

Posted by mota on Saturday, March 1, 2008 at 3:34am. THE MASS OF THE SUN IS ABOUT 10^27 METRIC TONS , OR 10^30 KILOGRAMS . HOW MANY KILOGRAMS ARE IN ONE METRIC TON ? ----------------------------- math - drwls 1000. ----------------------------- explain please i want to ...

### physics - last question

Sam is sitting in her fishing boat watching a trout swim below the surface. She guesses the apparent depth of the trout at 2.0m. She estimates that her eyes are about 1.0 m above the water's surface, and that the angle at which she's observing the trout is 45 degrees. b) ...

### Science-bobpursley

Thanks for helping me with al those parts bobpursley. If you have time, can you also check my questions please. Thank you very, very much in return. My post is on the second page.

### Physics

In my last post, I'm confused how drwls got P2/P1 = 14.8

### physics

Find the minimum diameter of a 51.5-m-long nylon string that will stretch no more than 1.01 cm when a load of 68.9 kg is suspended from its lower end. Assume that Ynylon = 3.51·10^8 N/m2 physics - bobpursley, Saturday, October 29, 2011 at 10:32am Hookes Law: elongation= force...

### physics

thanks for the answer drwls. can you please explain to me, how it happened?

### DRWLS,MATH,ALGEBRA

Drawls, How did you get 2h. and then the 2a/h from.Can you help me understand it when you get a chance. Directions: Solve each literal equation for the indicated variable. A=1/2h(B+b) (For b) Area of a trapezoid For Further Reading math,algebra - drwls, Monday, December 18, ...

### Physics Help me Someone plz

If a galaxy is traveling away from us at 2.0% of the speed of light, roughly how far away is it? t= light years I got 2.4x10^8 light years but its wrong please help me out...thank you Physics Plz help me - Anon, Monday, May 6, 2013 at 9:17pm 5.98x10^6 Thatz still wrong Physics...

### Physics, still don't get it!

I'm sorry bobpursley I don't understand your response, please clarify. When an object of mass m1 is hung on a vertical spring and set into vertical simple harmonic motion, its frequency is 12 Hz. When another object of mass m2 is hung on the spring along with m1, the frequency...

### Thanks

I would just like to sat thanks to drwls for helping me a bunch with the physics questions...AP physics is pretty hard..thanks again, whoever you are.. I am sure i will be back plenty of times!

### physics

thank you bobpursley

### physics

bobpursley pleas put more details on how you got your answers to my previous physics questions... thanks

### Physics-bobpursley please check

This is the question I posted about two hours ago and I worked it out two ways-could you scroll down and check it, please?If I have a roller coaster, and hill 1 height is 50cm and hill height 2 is 25 cm and the PE is .9 as it approaches the top of hill 2, how do I calculate ...

### Physics

Thanx DRWLS! Worked like a charm and I checked behind myself with the same formula!!!

### physics

Good job "Drwls", your answer to my bowling ball question worked. Way to go!

### PHYSICS, still cant get it

A man (weighing 915 N) stands on a long railroad flatcar (weighing 2805 N) as it rolls at 18.0 m/s in the positive direction of an x axis, with negligible friction. Then the man runs along the flatcar in the negative x direction at 40.00 m/s relative to the flatcar. What is ...

### Math CONTINUATION OF QUESTION FROM bobpursley

Thank you for answering the question before bobpursley, I understand how you did the deriv of inside, outside, but how do I now do the second derivative since you have the extra -18x^2 in the numerator?? Thank you very much! (I suppose I have to brush up on my derivatives) ...

### physics

for some reason, choice 6 was incorrect when i tried it sorry to keep bothering you about it drwls

### Physics to drwls question to answer given earlier

A 0.700-kg ball is on the end of a rope that is 0.90 m in length. The ball and rope are attached to a pole and the entire apparatus, including the pole, rotates about the pole's symmetry axis. The rope makes an angle of 70.0° with respect to the vertical as shown. What is the...

### physics multiplying vectors

n the product F = qv · B , take q = 4, = 2.0i + 4.0j + 6.0k and = 136i -176j + 72k. What then is in unit-vector notation if Bx = By? ~~may i get some assistance in this problem? so far.. i tried this.. 136i-176j+72k = 4(2.0i+4.0j+6.0k)(B) 136i-176j+72k = (8i+16j+24k)(B) [(...

### ATTN: DRWLS RE: PHYSICS

pete and john play a game of tug f war on a frictionless icy curface. pete weighs 539 N and john weights 392 N. during the course of the game, john accelerates toward pete at a rate of 3 m/s^2 a)what's the magnitude of the force that peter exerts on john? b)what's the ...

### Physics

bobpursley can you show the equasions you are using

### Physics

bobpursley, is answering questions on this all you do?

### Physics repost please check

Posted by Mary on Monday, November 5, 2007 at 8:21pm. Suppose that the electric field of an electromagnetic wave decreases in magnitude. Does the magnetic field increase, decrease, or remain the same? Account for your answer. For Further Reading Physics - bobpursley, Monday, ...

### physics

A 34 g glass thermometer reads 21.6°C before it is placed in 135 mL of water. When the water and thermometer come to equilibrium, the thermometer reads 38.7°C. What was the original temperature of the water? I need help on this please could someone please help out.Thank you...

### Physics

Sorry for reposting this but I'm still confused with the last part... You have been sent in a small spacecraft to rendezvous with a space station that is in a low circular Earth orbit, say, with a radius of 6,720 km, approximately that of the orbit of the International Space ...

### Physics

Sorry for reposting this but I'm still confused with the last part... You have been sent in a small spacecraft to rendezvous with a space station that is in a low circular Earth orbit, say, with a radius of 6,720 km, approximately that of the orbit of the International Space ...

### Physics

Sorry for reposting this but I'm still confused with the last part... You have been sent in a small spacecraft to rendezvous with a space station that is in a low circular Earth orbit, say, with a radius of 6,720 km, approximately that of the orbit of the International Space ...

### Physics please clarify

Posted by Mary on Monday, September 3, 2007 at 12:40pm. download mp3 free instrumental remix A charge of +2q is fixed to one corner of a square, while a charge of -3q is fixed to the diagonally opposite corner. Expressed in terms of q, what charge should be fixed to the center...

### physics

Posted by michelle quendarsv on Saturday, November 20, 2010 at 5:26pm. Posted by michelle quendarsv on Saturday, November 20, 2010 at 3:55pm. if it takes 726 watts of power to move a mass 36 meters in 14 seeconds, what is the mass? i really need like, step by step help please...

### physics

A horizontal segment of pipe tapers from a cross sectional area of 50 cm2 to 0.5 cm2. The pressure at the larger end of the pipe is 1.26 105 Pa and the speed is 0.029 m/s. What is the pressure at the narrow end of the segment? Pa Please help! physics - drwls, Monday, April 9, ...

### Physics

A horizontal segment of pipe tapers from a cross sectional area of 50 cm2 to 0.5 cm2. The pressure at the larger end of the pipe is 1.26 105 Pa and the speed is 0.029 m/s. What is the pressure at the narrow end of the segment? Pa Please help! physics - drwls, Monday, April 9, ...

### Physics

A horizontal segment of pipe tapers from a cross sectional area of 50 cm2 to 0.5 cm2. The pressure at the larger end of the pipe is 1.26 105 Pa and the speed is 0.029 m/s. What is the pressure at the narrow end of the segment? Pa Please help! physics - drwls, Monday, April 9, ...

### physics- response to bobpursley

which is false? Consider the following processes: I. Energy flows as heat from a hot object to a colder object II. Work is done on a system and an equivalent amount of energy is rejected as heat by the system III. Energy is absorbed as heat by a system and an equivalent amount...

### algebra 2

How is this problem done? IF f(x)=2x^2-8x-3 FIND f(-2) algebra 2 - bobpursley, Saturday, January 16, 2010 at 1:42pm Put in for x the value -2, and compute f(-2) algebra 2 - hellogoodbie, Saturday, January 16, 2010 at 1:47pm so is the answer f=21/2? if that is right, thank you ...

### algebra 2

How is this problem done? IF f(x)=2x^2-8x-3 FIND f(-2) algebra 2 - bobpursley, Saturday, January 16, 2010 at 1:42pm Put in for x the value -2, and compute f(-2) algebra 2 - hellogoodbie, Saturday, January 16, 2010 at 1:47pm so is the answer f=21/2? if that is right, thank you ...

### Physics repost please check

Good morning. This is a repost. The system is telling me my calculations is incorrect. I thought a fresh pair of eyes would help. Please tell me what I am doing wrong. Suppose a monatomic ideal gas is contained within a vertical cylinder that is fitted with a movable piston. ...

### Physics please clarify

Posted by Mary on Monday, September 3, 2007 at 12:40pm. download mp3 free instrumental remix A charge of +2q is fixed to one corner of a square, while a charge of -3q is fixed to the diagonally opposite corner. Expressed in terms of q, what charge should be fixed to the center...

### To drwls

I posted some Physics questions yesterday, but no one got the chance to look at them, so can u please go to 2nd page and look through them.

### physics Again

bobpursley can you please check my reply to your post about my question? I am not sure if I did my equation correctly. Thanks

### physics

Bobpursley; you helped me with my question and I am a little stuck how would I find distance if I don't know time and vice versa?

### Physics (CHECK)

One student is pushing on a chair with a force of 260.6 N directed at an angle of 30 degrees above horizontal while a second student pushes on the same side of the chair with a force of 21.0 N at an angle of 15 degrees below horizontal. What is the magnitude, in N, of the sum ...

### Reiny or Damon or Bobpursley

Express the series 11 + 18 + 27 +...+ 171 using sigma notation. Usually you would take 27-18 and that's the step between numbers, right? (I think its the k-value?) But 27-18=9 and 18-11=7. Are we stepping by k+2 here? Like k, k+2 k+4, k+6...? Please help me. I'm not confident ...

### acceleration estimate(bobpursley)

Well, bobpursley explained this to me. I didn't understand this well. Since there was an error in the data, I am posting it again t(sec) v(ft/sec) 1 12.2 1.5 13 2 13.4 2.5 13.7 velocity of an object moving along a line at various times. How do I estimate the object's ...

### Physics

if it takes 726 watts of power to move a mass 36 meters in 14 seeconds, what is the mass? i really need like, step by step help please? asap. thanks, michelle . physics - bobpursley, Saturday, November 20, 2010 at 4:06pm power= work/time= mass*g*distance/time mass= power*time/...

### Physics - Repost

I am reposting the this question. Find the current in the 10.0 ohm resistor in the drawing (V1 = 21.0 V and R1 = 27.0 ohms). The drawing is in the shape of a rectangle that has one straight line down the center. On the left top line is R1; on the right top line is 5.0 ohm; on ...

### Physics- drwls please help

A certain CD has a playing time of 80 minutes. When the music starts, the CD is rotating at an angular speed of 4.8 x 10^2 revolutions per minute (rpm). At the end of the music, the CD is rotating at 2.1 x 10^2 rpm. Find the magnitude of the average angular acceleration of the...

### physics

A car weighing 9800 N travels at 30 m/s. What braking force (to the nearest whole number) brings it to rest in 100 m???? THNX BOBPURSLeY

### Algebra-please check

Could someone please check my solution-Thank you-DRWLS helped me set it up and I solved it, I think From the top of a mountain 150 feet high, Jessie stands at the safety rail on the edge and looks below. The angle of elevation from his bike on the ground to Jessie is 38 ...

### physics

i posted this question before however i did not understand drwls explanation. anybody else want to try ? Sam tosses a ball horizontally off a footbridge at 3.1 m/s. How much time passes after he releases it until its speed doubles?

### Chemistry!! - bobpursley please

Calculate the maximum wavelength of light capable of removing an electron for a hydrogen atom from the energy state characterized by the following when n=4 =__________nm Responses Chemistry!! - bobpursley, Wednesday, October 22, 2008 at 4:05am So the two energy states are n=4 ...

### physics

DRWLS: PLEASE SEE ADDITIONAL INFO AT THE BOTTOM its the second part of the question that I don't understand: according the graph shown, the net force acting on an object varies wth the object's displacement. Calculate the work down by the force on the object at the various ...

### Physics-bobpursleyplease check

This is the question I posted about two hours ago and I worked it out two ways-could you scroll down and check it, please?If I have a roller coaster, and hill 1 height is 50cm and hill height 2 is 25 cm and the PE is .9 as it approaches the top of hill 2, how do I calculate ...

### Re: PHYSICS

A man (weighing 915 N) stands on a long railroad flatcar (weighing 2805 N) as it rolls at 18.0 m/s in the positive direction of an x axis, with negligible friction. Then the man runs along the flatcar in the negative x direction at 40.00 m/s relative to the flatcar. What is ...

### Physics

You have been sent in a small spacecraft to rendezvous with a space station that is in a low circular Earth orbit, say, with a radius of 6,720 km, approximately that of the orbit of the International Space Station. Due to mishandling of units by a technician, you find yourself...

### Physics bobpursley

Give some examples of applications that resulted from work done by physicists on superconductivity? Don't understand this. I only got wires as an answer which totally doesn't seem correct.

### physics: BOB or DRWLS follow up question

What average force is required to stop an 1100-kg car in 8.0 s if it is traveling at 95 km/h? i understand what you both did, but why can't you use the V = Vo + at equation and solve for acceleration there and use that in the EF = ma equation?

### physics

a 2.5 kg rifle fires a 20 g bullet at 400 m/s. What is the magnitude of the recoil velocity of the rifle? I still don't understand. Could you please help with a formula? Thank you. physics - drwls, Monday, February 7, 2011 at 6:38pm Try using conservation of momentum. recoil ...

### Physics - drwls

Posted by winterWX on Monday, March 19, 2007 at 11:51pm. A 2600 kg truck traveling north at 38 km/hr turns east and accelerates to 55 km/hr. What is the change in the truck's kinetic energy? What is the magnitude of the change in the linear momentum of the truck? What is the ...

### Math

I got it! Thank for your help, drwls.

### drwls

Thank you very much.

### physis

to DRWLS thanks for the help DEEK./

### Physics (thx drwls, bobpursley)

After reaching terminal velocity, a raindrop of m=3.06E-4kg falls vertically down a distance of 500m. a)what is the work done by the force of gravity on the raindrop? sol) since the displacement is in the same direction as the force, the work done is Fcos90 = 0. (correct?) b) ...

### English

I am new and I have questions. Are there any teachers in this website? If there are teachers in this website WHAT ARE THEIR NAMES? I could write to them in this website when I need help with my homework LIKE: Name:Kaveri Subject: To:Teacher (Name of the teacher) If there are ...

### math. HOW DO I CONVERT A DECIMAL TO A FRACTION

how do i convert a decimal to fraction in SIMPLEST FORM? a) -2.756 ?? Write out the 0.756 as 756/1000, then reduce it to lower terms if you can. Since both numerator and denominator are evenly divisible by 4, 756/1000 can be reduced to 189/250. The mixed number becomes -2 189/...

### DRWLS

THANKS WHAT IS WRONG WITH ESTAR IN NUMBER

### Physics - Frequency

This is in reply to a previous post, I'm not really sure whether replies to posts that are several days old are viewed by anyone, so I'm reposting just in case. In reply to bobpursley's post, I just want to ask, how would you know how long it takes for the sound to reach you? ...

### Site not working correctly/Physics

I posted a question a couple of days ago which was answered by DRWLS - thank you. Unfortunately I am unable to read the guidance provided as the typing is obscured by the adverts down the right hand side of the page. Look forward to replies. Thanks Mike

### Physics

if it takes 726 watts of power to move a mass 36 meters in 14 seeconds, what is the mass? i really need like, step by step help please? asap. thanks, michelle . physics - bobpursley, Saturday, November 20, 2010 at 4:06pm power= work/time= mass*g*distance/time mass= power*time/...

### drwls

thankyou for your help its helped me alot you are a star!

### Physics Drwls

I was wanting help with my physics post and since no one replied I thought there wasn't a physics tutor on Jiskha, but came back on today cause I really need to get a hang of my physics stuff and luckily seen you Drwls. A bike rider approachea a hill with a speed of 8.5m/s. ...

### Physics

physics - drwls, Sunday, January 24, 2010 at 2:50am Compute the angle of the strings from vertical. It is sin^-1 (8.5/40) Call this angle A If the string tension is T T sin A = F (the Coulomb force) T cos A = M g tan A = F/Mg You need to say what the units of the mass are. All...

### 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 not ...

### TO drwls

I just wanted to say THANK YOU so much. You're a lifesaver!

### drwls

Thank you for your help, & for the website, makes for some interesting reading.

### To: Drwls

can you please check my previous science post, thanks