# Search results

1. ### Electric Field between two charges

I have put it still doesn't make sense. You cannot ignore the negative sign, can you?
2. ### Electric Field between two charges

actually...i js noticed your second point... both charges act in the same direction so the null point can't be inbetween the charges. But why have you ignored the negative sign ??
3. ### Electric Field between two charges

this is exactly what I got, except for one small difference. The charge of the second particle is negative, why have u ignored it??
4. ### Electric Field between two charges

GOD! This website is soo useless!
5. ### Electric Field between two charges

Homework Statement Two charges of value +4C and -16C are separated by a distance of 3m. At what spot along the line is the electric field is zero? Homework Equations I tried using the equation E = Q / 4pieE(o)r^2 The Attempt at a Solution I get a quadratic equations which...
6. ### I need someone to check my final answer

Homework Statement If I was to work out the sum of all the even numbers between 1000 and 2000, am I correct in saying that there are exactly 600 even numbers? Therefore, is the final answer 959400? Could someone please confirm this? Thank you. Homework Equations Sum = n/2[(2a+(n-1)d]...

8. ### Volume of observable universe

Ok. I gave it a little thought and worked it out. The volume of the obserbavle universie is 9.73E78 m^3. But the question carries on. It goes: A beach is 1km long, 10m across, and 1m deep. One sand grain occupies 1cubic mm. which is the larger number: The number of stars in the...

10. ### Volume of observable universe

Maybe not. But how else am I supposed to work this out? Do I need to know the rate at which the Universe expands??
11. ### Volume of observable universe

This question seems simple but I cannot recall the formula to solve it. I hope someone can help me: If the age of the universe is 1.4E10 years, estimate the volume of the observable universe?:confused: Urgent help required.
12. ### Finding Initial Velocity: Projectile Motion Problem

A particle is projected on a horizontal ground and moves freely under gravity. The horizontal and vertical components of the initial velocity are 2u and u ms^1 respectively. The ball lands a distance 80m from the point of projection. Show that u=14 This is what I did: Taking motion...
13. ### Moving bicycle

This question has been bothering me for time. How does a moving bicycle manage to stay upright? but when it slows down it tends to fall to a side. Can someone please explain?
14. ### Uniform semicircular lamina question

Can someone please explain to me how to start off this question? A uniform semicircular lamina has mass M. A is the midpoint of the diameter and B is on the circumference at the other end of the axis of symetry. A particle of mass m is attached to the lamina at B. The centre of mass of the...
15. ### Take care of the environment and buy an electric car

Bikes don't attract the girls hehe.
16. ### All floor friendly material

I love that idea.
17. ### All floor friendly material

What do you mean?
18. ### All floor friendly material

I woudl love it if it did both. But just avoiding damage would do.
19. ### Take care of the environment and buy an electric car

Oh right. So it doesn't really make a difference. I might as well drive a normal petrol car then.
20. ### Uniform Lamina

Oh sorry. Haha. I didnt realize there was invisible ink on the paper.
21. ### Uniform Lamina

Can you be of more help please?
22. ### Uniform Lamina

Where is the centre of mass of a semicircular lamina which is uniform? I know it is somewhere along the line of symestry, but where excactly?:confused:
23. ### All floor friendly material

I am going to design a chair for my school project. The legs of the chair have to be friendly to all types of floors e.g. carpet, floor board etc. The legs are made of wood, but I am looking for a material that I can cover the bottom of the legs with to protect the floor. Any suggestions?
24. ### Take care of the environment and buy an electric car

I am concerned about our environment, and do my best to keep it clean as much as possible. I am going to buy a car soon, and I am looking for an electric car. When I was doing my O'levels, I learned about electromagnetic induction, producing an electric current from changing magnetic field...
25. ### Metal tubes project for school

Well, I am not going to bend it much. It is a long vertical metal tube bent slightly inwards at the top (about 1/4 of the whole length of the tube). The tube is 10mm in diameter. I am thinking about using stainless steel, and I want it to be perfectly bent.
26. ### What will be the speed of the wave on this string?

If I knew where to start, or if I have done some working, would I be here?
27. ### Metal tubes project for school

I am designing a product for my school project. I need to bend two pieces of metal tubes. This is not possible in my school, therefore I need to get it done elsewhere. Can someone suggest where I could go? Which comanies to approach.:confused: Please help, my time is running out. PS. I live...
28. ### What will be the speed of the wave on this string?

:confused: Suppose you have a string with a linear density of 26.9g/m. A tension of 57.9 N is applied to this string. What will be the speed of the wave on this string?
29. ### Finding derivative of y + 1/(y+3)

That gives me dA/dy= 1 - 1/(y+3)^2. Is that right?
30. ### Finding derivative of y + 1/(y+3)

Sorry, confused. I just don't know how to start the question in the first place.
31. ### Finding derivative of y + 1/(y+3)

Well I tried to make the equation simpler first. y + 1/(y+3) = (y^2 + 3y + 1)(y+3)^-1 right so far?
32. ### Finding derivative of y + 1/(y+3)

Hi, I am stuck on this question. Can someone please help me as quick as possible, I am revising for an exam on Monday. If A= y + 1/(y+3) , find dA/dy. I have been tryin to solve this question but I keep getting the wrong answer.:confused: :confused:
33. ### The energry of an electron

The kinetic energy of an electron is 2.00 eV. Find the wavelength. I used E=h(c/n) where n=wavelength. But the answer comes out wrong, please help.
34. ### Electron energy

An electron has kinetic energy 2.00 eV. Find the wavelength. I used E=h(c/n) where n=wavelength. But the answer comes out wrong, please help.

36. ### Trig Identity

Sorry I don't understand. And I am trying to apply the double angle formulae but I am just getting confused.
37. ### Trig Identity

Prove the identity: sinA / (1+cosA) = tan (A/2). Im going no where with this, please help?:confused: :confused:
38. ### Trig Identity

tan2A (2cosA/sin2A) = tan2A (2cosA/ (2sinAcosA)) = tan2AcosecA. Safe boys!:biggrin:
39. ### Trig Identity

I got as far as simplifying the equation to 2cosA / cos2A. What now?

42. ### Potential energy of the system increase or decrease?

No, this is a question where numerial values are given. I thought that the totla potential energy stays the same because they both move off in differnt directions
43. ### Potential energy of the system increase or decrease?

When two electrons move away from each other, does the potential energy of the system increase or decrease?
44. ### Component Identities

Yeh, but I can't simplify anything to solve the problem
45. ### Component Identities

Solve for x 3sin(x+10)=4cos(x-10) I tried changinf everything into tan nothing out. I tried expaning the brackets and collecting like terms, that didnt work out either. Please help.
46. ### Tension in the spring

I think this question is complicated, and I don't even know how to start it off, please help? A mass of 2 kg is hung from the lower end of a spiral spring and extends it by 0.4m. When the mass is displaced a further short distance x and released, it oscillates with acceleration a towards the...
47. ### Assistance with Projectiles

Sorry I am confused! Could you go through the question please?
48. ### Aeroplane velocity problem

Yes, that true.
49. ### Aeroplane velocity problem

Oh right!. So Vx=400cos2 and Vy=400cos88.
50. ### Assistance with Projectiles

But how can I show that angle of depression is 45 degrees on that diagram?