Physics - November 2007

PLEASE EXPLAIN BRIEFLY AND LABEL ANSWERS!

An object is located 3.5cm from the optical centre of a lens. The lens produces an image of magnification that is +0.667 the size of the object.

a) Is this lens a diverging or a converging lens? Explain your answer.

b) Find the position of the image and the focal length of the lens using the magnification equation and the thin lens equation.

2007-11-22 14:52:42 · 1 answers · asked by Deloris 1

If density or mass does affect acceleration, then how can they conclude that every object accelerates at 9.8 m/s^2 on earth.

2007-11-22 14:23:21 · 6 answers · asked by Dream.Big 4

where could i go to or how could i create a numbers generator and be able to program it to stop on certain past number sequences to develope a pattern for upcoming numbers

2007-11-22 13:39:05 · 1 answers · asked by howdog_03 1

I just can't visualize it at all. No equations please. I have zero math skills. Explain the theory of relativity to me like I was a four year old.

2007-11-22 12:40:32 · 3 answers · asked by ricnoodle 4

How accurate is it?

2007-11-22 11:20:47 · 2 answers · asked by H I 1

we directly experience 4 dimensions - 'up/down', 'in/out', 'side-to-side' and time, right?
how come we only experience the last one as being 'uni-directional'...if i understand it right then mathematically there's no reason for this?(i mean that time only goes one way for us,PLEASE put me right if i ain't!)...

my THOUGHT was that time was the dimension that we experience the other three 'in', as it were and that if we were in a fifth dimension that 'contained' space/time then we would be able to move back and forwards in time as easily as i can move up and down etc. is that right?

if so - how come the dimension at the top of my hierarch is directional? if we could experience a fifth dimension would THAT be one-directional like time is for us now? and - this is the important bit for me - WHYYY!!!????

any elucidating concepts would be appreciated, ty.

2007-11-22 11:01:13 · 7 answers · asked by mlsgeorge 4

2007-11-22 09:04:37 · 5 answers · asked by Anonymous

An electron is released a short distance above the surface of the Earth. A second electron directly below it exerts an electrostatic force on the first electron just great enough to cancel the gravitational force on it. How far below the first electron is the second?


Anyone who can help me with this

2007-11-22 06:27:21 · 3 answers · asked by Hammad A 1

Two solid stainless steel, conducting spherical balls, of radii r1 = 2.0 cm and r2 = 10.0 cm, are connected by a thin copper wire, as shown in the figure (click on link below for figure). The spheres are 1.00 m apart, center-to-center. A total charge of Q = 12 microC is shared by the two spheres.

Link for figure: http://img108.imageshack.us/img108/5205/physicszs5.jpg

a) What are the charges Q1 and Q2 carried by the ball #1 (on the left) and ball #2 (on the right), respectively?

b) Taking the potential at infinity to be zero, what is the electric potential at the surfaces of the two spheres?

c) What are the electric fields just inside the spheres?

d) What are the electric field magnitudes just outside the spherical surfaces, and in what directions do they point?

e) What are the electric field x- and y- components, and also magnitude and direction, at a point P, 1.00 m away from the wire along the y-axis, as shown in the figure?

This is the review for my test. Please help. Thanks

2007-11-22 05:39:59 · 2 answers · asked by 123haha 1

(a) Give an example in which the net force acting on an object is zero, yet the net torque is nonzero. (b) Give an example in which the net torque acting on an object is zero, yet the net force is nonzero.

2007-11-22 05:39:27 · 2 answers · asked by boy101 3

i need it for a project

2007-11-22 05:33:28 · 3 answers · asked by Anonymous

Please respond if you know which one it is and why, i need help!

2007-11-22 05:00:29 · 14 answers · asked by chordlover12345 1

i have a video recording of a person's weight as it changes while the elevator accelerates, comes to a constant speed, and decelerates to a stand-still.

how do i figure out the height the elevator traveled to? equations would be best, as i will put in my own data. THANKS!

2007-11-22 04:37:52 · 3 answers · asked by kms107 2

Explain why the relativistic Lagrangian is expressed as L = T' - U, where

T' = - m0 c² √(1-(v/c)²)

instead of L = T - U, where T is the relativisitc kinetic energy,

T = (m0 c²) / √(1-(v/c)²) - m0 c²

2007-11-22 04:36:54 · 2 answers · asked by Scythian1950 7

A marble rolls off the edge of a table that is 0.734 m high. The marble is moving at a speed of 0.122 m/s at the moment that it leaves the edge of the table. How far from the table does the marble land?

Can someone please explain how to do this please?!?! Thank you.

2007-11-22 04:27:43 · 2 answers · asked by ☺♠JonasJay♫♦ 5

A 0.45-kg ball is attached to the end of a cord of length 1.4 m. The ball is whirled in a circular path in a horizontal plane. The cord can withstand a maximum tension of 57.0 N before it breaks. What is the maximum speed the ball can have without the cord breaking?

Can someone please explain to me how to do this? I would be very thankful. Please help me. Thank you.

2007-11-22 04:24:17 · 5 answers · asked by ☺♠JonasJay♫♦ 5

The moon revolves around the Earth in a circular orbit with a radius of 3.84 x 10^8 m. It takes 27.3 days for the moon to complete one orbit around Earth. What is the centripetal acceleration of the moon?

Please help me....I have clue hoe to do this....I promise to give 10 to the best answer! Thanks!

2007-11-22 04:20:02 · 2 answers · asked by ☺♠JonasJay♫♦ 5

Just a question that popped in my exam... Happened to be only I missed:

The sum of the potential and kinetic energies of a system is said to be conserved when

A) Only when the resultant force acting on the system is zero
B) Only when it moves in a closed cycle
C) Only when the work done by the resultant external force is zero
D) Always
E) None of the above

(or something like that)

I can't understand why A and C are wrong anyways.

2007-11-22 03:58:40 · 4 answers · asked by RenaissanT 3

Why don't Neon lasers or helium lasers exist on their own, and instead they are combined to form He-Ne lasers?

2007-11-22 03:56:04 · 1 answers · asked by Kush 2

A moving object has a kinetic energy of 182 J and a momentum with magnitude of 28.2 kg·m/s.
(a) Determine the mass of the object.
(b) Determine the speed of the object.

2007-11-22 03:29:49 · 3 answers · asked by andyjumpman23 3

bonus question explain how you woul measure 1 gram of water

2007-11-22 03:28:18 · 2 answers · asked by aj mc cake 1

A 0.220 kg block on a vertical spring with spring constant of 4.20*10^3 N/m is pushed downward, compressing the spring 0.053 m. When released, the block leaves the spring and travels upward vertically. How high does it rise above the point of release?

2007-11-22 03:25:14 · 2 answers · asked by andyjumpman23 3

Hi I want to write a report of about 1000 words on students misconceptions on the topic of forces for KS3 physics - children aged 11-16.

So was wondering if you could offer misconceptions regarding forces for children this age that I can add to my list that I am compiling.

thanks

2007-11-22 03:15:15 · 6 answers · asked by Anonymous

A 1.9 kg ball is attached to a ceiling by a string. The distance from the ceiling to the center of the ball is 1.19 m, and the height of the room is 3.00 m.

2007-11-22 02:37:40 · 5 answers · asked by Anonymous

2007-11-22 02:30:38 · 2 answers · asked by kakiba 1

Place yourself facing the edge of an open door. Position your feet astride the door with your nose and abdomen touching the door's edge. Try to rise on your tiptoes. Why can't this be done?

Please help, this is a physics txtbook question found in a chapter about, momentum, impulse, and center of mass. Thank you!

2007-11-22 01:08:11 · 2 answers · asked by Callie 1

Find the vector sum of the following four displacements on a map: 60m north; 30m west; 40m at 60degree west of north; 50m at 30 degree west of south. solve graphically and also algebraically.

2007-11-22 00:41:43 · 2 answers · asked by beutifulgirl 3

The type Im referring to is a program that can fight off the side of humanity which is increasingly turning evil. Humans just cannot last long enough to stand against the changing mentality of this evolving world. Need to create something which does the right thing. (although I realize right and wrong are relative). Something which can distinguish and defend.

2007-11-22 00:11:03 · 2 answers · asked by somebot 1

Explain the common phrase in electrical safety: It’s not voltage that kills, it’s current

2007-11-21 22:39:19 · 5 answers · asked by sunday 1

What I mean is, what does the Tesla unit mean, and what are it's implications as far as the energy involved in what it is describing?

2007-11-21 22:08:29 · 2 answers · asked by Anonymous