# Search results

1. ### How to prepare 500 mL of 0.025 M of Glucose solution?

Homework Statement : I am using a virtual chemistry laboratory and the directions for the first lab experiment says to prepare 500 mL of 0.025 M of glucose solution by diluting the 1 M glucose solution. (I am re-posting this question due to the fact that the previous one was deleted because it...
2. ### B Why do black holes have infinite density, mass, and gravity?

If stars have finite mass, gravity, and density, why does a black hole have infinite density, mass, and gravity and why doesn't it attract everything around it with such infinite gravity? Also, with infinite density, why are black holes all different sizes?
3. ### B The position of a particle/electron question

When scientists say the position of a particle or electron cannot be known at the same time as its speed, do they mean the particle's position in reference to jumping from energy levels in a single atom, the position in reference to traveling around the nucleus of an atom, or do they mean...
4. ### A Source for First Physics and Chemistry Research Papers?

I want to know if there is a good online source to find and read first-time research papers written by undergraduates(bachelor's research papers) to get a feel for how to write a first research paper in Physics or Chemistry. Can you give me some good places online?
5. ### Find the distance between Helsinki and Seattle.....

Homework Statement This is an astronomy problem. I know how to find cos(AOB) but I am not sure what to do after this. Find the distance between Helsinki and Seattle along the shortest route. Where is the northernmost point of the route, and what is its distance from the North Pole? The...
6. ### B A Speed of Light Theoretical Question

Let's say a mother ship is traveling at the speed of light. If you shoot a pod out of the mothership at the speed of light(and that pod is already traveling at the speed of light), then wouldn't that pod be traveling at twice the speed of light? And if you have a second pod speeding away from...
7. ### Applying Newton's Universal Law of Gravitation

Homework Statement This problem only requires to find h, but I want to make sure that I also found Me and g correctly. Starting with Newton's Law of Gravitation, determine the height h one person has to go from the surface of the earth in order for that person's weight to be reduced to...
8. ### Simplifying a fraction

Homework Statement Simplify (6x+12y)/(10a +5) times (100a2 - 25)/(9x2 - 81y2) Homework Equations (6x+12y)/(10a +5) times (100a2 - 25)/(9x2 - 81y2) The Attempt at a Solution (6x+12y)/(10a +5) times (100a2 - 25)/(9x2 - 81y2) = 3(2x+4y)/(10a+5) times (4a - 1)/(3x-27y) =...
9. ### Did I get this right? Simplifying a fraction

Homework Statement Simplify: (a2 + 2ab + b2)/(a2 - b2) times (a2 - 2ab + b2)/(a2 - b2) Homework Equations (a2 + 2ab + b2)/(a2 - b2) times (a2 - 2ab + b2)/(a2 - b2) The Attempt at a Solution Did I simplify this correctly?? (a+b)(a+b)/((a-b)(a+b)) times (a-b)(a-b)/((a-b)(a+b)) = ((a+b)/(a+b))...
10. ### Multiplying a fraction

Homework Statement I would just like to know if I got this right. ((x2 + 2x + 1)/(18cw3) times ((12c3w)/(x2 - 1)) = (12c3wx2 + 2x12c3w + 12c3w)/(18cw3)(x2 - 18cw3 Homework Equations ((x2 + 2x + 1)/(18cw3) times ((12c3w)(x2 - 1)) The Attempt at a Solution (12c3wx2 + 2x12c3w +...
11. ### Calculate the mass of F2 required to combine with N2...?

Homework Statement a) Calculate the mass of F2 required to combine with N2 to produce 204 kg of NF3? b) what mass of N2 exactly combines with 25.91 mg of F2? Homework Equations Equation: N2 + 3F2 ---> 2NF3 Convert 204 kg to grams 204 kg X 1000 grams = 204,000 grams atomic mass of N = 14.0067 u...
12. ### What mass of P4 is required to combine with 0.398 g of Cl2?

Homework Statement I have tried and tried and I can't figure out the factors to use on this: a) What mass of P4 is required to combine with 0.398 grams (g) of Cl2 to produce PCl3? b) What mass of PCl3 results when 0.398 g of Cl2 is combined with the calculated mass of P4? I know that the...
13. ### What mass of oxygen is liberated?

Homework Statement This is a solved example problem in my chemistry book: What mass of oxygen gas O2 is liberated when a 2.5 gram sample of sodium nitrate NaNO3 is heated? Please keep in mind that I am self-studying, I am not currently in chemistry class. Homework Equations 2NaNO3 ---> 2NaNO2...
14. ### Job Skills What do you suggest for someone with Asperger's in Science?

What do you suggest as far as tips for interviewing and interacting with team members for someone who is wanting to go into research in a Chemistry or Physics field who is shy and has always had difficulty with eye contact and has been diagnosed with Asperger's? Also, do you have Asperger's as...
15. ### Solve a linear equation

(x - 2)^3 = x^2(x - 6) = (x^3 - 8) = (x^3 - 6x^2) (x^3 - 8) = (x^3 - 6x^2) -x^3 -x^3 = -8 = -6x^2 I am not sure how to solve this for x
16. ### Finding the initial velocity of a projectile, given time, an angle, and distance

Homework Statement A baseball is thrown at 20 degrees to the horizontal. The ball travels a horizontal distance of 18 meters when it returns to the same level as the instant it had been thrown. The total time it traveled between these points is 2.1 seconds. Determine the initial velocity (Vo)...
17. ### Projectile motion at an angle

Homework Statement A bullet leaves a gun at an angle of 40 degrees to the horizontal. It reaches maximum height in 1.3 seconds. Determine the speed (velocity) with which the bullet left the gun (aka initial velocity of bullet). Homework Equations 1. t = (Vfy - Voy) / -9.8 m/s/s 2. Vosin40...
18. ### Projectile Motion at an Angle

Homework Statement You throw a ball. The ball leaves your hand with a velocity of 15 m/s at an angle 60 degrees above the horizontal. Acceleration due to gravity is 9.8 m/s/s. a) Determine the velocity (magnitude and direction) of the ball at the maximum height. b) How much time does it...
19. ### Change in potential and kinetic energy

Homework Statement how is the change in potential energy related to the change in kinetic energy? Homework Equations i just know that for a tossed object, the KE decreases, and its PE increases until it reaches the top. Then it has potential energy at the top, and its KE increases...
20. ### True or False:Gravitation & Circular Motion Concepts

Homework Statement Give reasons why you regard each of the following statements as true or false. Include appropriate equations and explanations using underlying basic physics concepts and laws. a) The condition for uniform circular motion of any object is that its velocity and speed must be...
21. ### Elevators and Force

Homework Statement A 60 kg person is standing in an elevator. Calculate each one of the forces acting on the person while the elevator is: a) at rest, b) moving up with a constant velocity of 3m/s, c) accelerating down at 4m/s^2, d) accelerating up at 4m/s^2. Homework Equations Force...
22. ### Newton's Law of Gravitation

Homework Statement Starting with Newton's law of gravitation, determine the height h one person has to go from the surface of Earth in order for the person's weight to be reduced to 1/5 of their weight at the surface of the Earth. The only information you are given is that the radius of the...
23. ### Magnitude and Direction of Velocity (projectile motion)

Homework Statement A baseball is thrown. The ball leaves your hand with a velocity of 15 m/s at 60 degrees above the horizontal. acceleration due to gravity is 9.8 m/s^2. Determine the velocity (magnitude and direction) of ball at the maximum height. Homework Equations im not sure, but...
24. ### Physics and Continuity Graphs

This is not a homework question--I am just curious to know if there are any connections between calculus graphs involving continuity (say, a hole in a graph, which we are studying in my first under-graduate Calculus course), and the types of limit problems used in physics. i understand that in...
25. ### Astronomy-related career

can i get into an astronomy-related field using a B.S. in physics? i enjoy physics but i also really enjoy astronomy.
26. ### Area approximation and (riemann?) sums

Homework Statement I am a first-year physics student learning calculus. my question is about the approximation of the area of a region bounded by y = 0. Homework Equations Use rectangles (four of them) to approximate the area of the region bounded by y = 5/x (already did this one), and y =...
27. ### Difference between calcultaed slope and slope given on the graph?

Homework Statement When question is asked: "How close is the slope (from an X-t graph) you calculated and the value actually displayed on the graph?"---does this mean you simply subtract your calculated velocity(slope of X-t graph) from the slope actually given on the graph? Homework...
28. ### Development of Intelligent Life?

Why do some scientists assume that intelligent life may be rare--that because only one high-intelligence--homo-sapiens (us) developed on Earth, that inteligent life is rare to evolve throughout the universe? Instead of seeing it that way, why can't you turn that thought around and assume that...
29. ### Understanding horizontal and vertical components of a falling object

I want to understand this: In the case of a dropped object, the horizontal component of the velocity with which the object hits the ground is not the same thing as the horizontal velocity itself, am i right? The horizontal component of the velocity when the object hits the ground means the...
30. ### Infinite energy and conservation

doesnt the fact that a magnet's field going from one end to another perpetually, constitute infinite energy? also, dont particles disobey the conservation law because where do particles get their energy from? particles are always moving. they never stop. but why is matter only destroyed if a...