Physics - March 2007

I am an A level Physics student trying to understand circular motion. If there's a force on a particle perpendicular to the velocity, then this creates an acceleration on the particle in that direction, right?

So to my mind, this should mean that the 'speed in that direction' increases from zero, and the particle keeps the speed it originally had AS WELL, at 90 degrees to the new increased speed, which means an overall increase in speed due to Pythagoras' theorem... but no, the speed stays the same, and only its direction changes. Where am I going wrong here? I can do the maths and get the answers out, but I don't understand just HOW it works.

2007-03-28 12:31:39 · 5 answers · asked by rissaofthesaiyajin 3

In a Young's double-slit experiment the separation distance y between the second-order bright fringe and the central bright fringe on a flat screen is 0.0191 m, when the light has a wavelength of 425 nm. Assume that the angles are small enough so that sin theta is approximately equal to tan theta. Find the separation y when the light has a wavelength of 601 nm.

2007-03-28 12:30:56 · 1 answers · asked by Boober Fraggle 5

science

2007-03-28 12:19:13 · 5 answers · asked by Anonymous

2. A person with dry skin has a resistance from one arm to the other of about 1 x 10^5 Resistance. When the skin is wet, resistance drops to 1.5 x 10^3 Resistance.

a. What is the minimum voltage placed across the arms that would produce a current felt by a person with dry skin?
b. What effect would the same voltage have if the person had wet skin?
c. What would be the minimum voltage that would produce a current that could be felt when the skin is wet?

2007-03-28 12:15:59 · 1 answers · asked by truckee 1

2007-03-28 12:00:04 · 6 answers · asked by Anonymous

2007-03-28 11:55:37 · 11 answers · asked by matt p 2

2007-03-28 11:55:31 · 11 answers · asked by Anonymous

The graph shows the net external force component Fcos(theta) along the displacement as a function of the magnitude of the displacement s. The graph applies to a 56 kg ice skater.

link to graph: http://i48.photobucket.com/albums/f226/buttrefly18/06_71.gif

(a) How much work does the net force component do on the skater from 0 to 3.0 m?

(b) How much work does the net force component do on the skater from 3.0 m to 6.0 m?

(c) If the initial speed of the skater is 2.5 m/s when s = 0, what is the speed when s = 6.0 m?

2007-03-28 11:53:52 · 1 answers · asked by softball579 1

If one has a timeship and goes backwards, would one be stuck taking the path previously taken forwards, because the ship cannot occupy the same space as it's past space? Also if one were to travel forward, would movement be restricted in space?

2007-03-28 11:51:21 · 2 answers · asked by Luis 6

In terms of what it is made of!

2007-03-28 11:44:46 · 6 answers · asked by jessieb389 1

Two stars are 4.4 x 10^11 m apart and are equally distant from the earth. A telescope has an objective lens with a diameter of 1.28 m and just detects these stars as separate objects. Assume that light of wavelength 540 nm is being observed. Also, assume that diffraction effects, rather than atmospheric turbulence, limit the resolving power of the telescope. Find the maximum distance that these stars could be from the earth.

2007-03-28 11:40:58 · 4 answers · asked by Boober Fraggle 5

Ok, so I'm having a "discussion" (arguement) with my sister's boyfriend. He is telling me that light STOPS when it hits a wall and also STOPS when it hits a window.

I don't agree. I think that when light hits glass it goes on to the other side...maybe even "fans out" in all directions. I think that when it hits a hard surface it bounces off back into the room.

I don't think that light just STOPS when it hits something.

What do you all think?

If I'm right, can I get a link of something so that I can shove it in his smug face?

If I'm incorrect let me know so that I can learn something...........and appologize.....

2007-03-28 11:35:10 · 3 answers · asked by Gwenith O 3

An object of height 2 mm is placed 40 cm to the left of a converging lens whose focal length has magnitude 20 cm
a. completely describe the image. Is the image real/ virtual, upright.inverted? What is the location, heightm and magnification of the image?

2007-03-28 11:18:15 · 1 answers · asked by PreTty in PiNk 2

the corner of a prism (n=1.2) is a 45 degree angle. The incident light makes an angle (theta) with respect to the normal, as shown. if (theta) is larger than some angle (theta)o, the light is totally reflected at the second face of the prism. find (theta)o

2007-03-28 11:13:42 · 1 answers · asked by PreTty in PiNk 2

a man stands on theroof of a 15 m tall building and throw a rock with a velocity of magnitude 30m/s at the angle of 33 above the horizontal the max heigh above the roof and the velocity of the rock before it strickes the ground and the horizental distance from the base of the building to the point where the rocket just strikes the ground

2007-03-28 11:08:18 · 4 answers · asked by loveiranshiraz 1

2007-03-28 11:05:50 · 2 answers · asked by carlamaria 1

i'm going to try to make a rubens' tube similar to one that i saw on youtube that is made from pvc pipe as a project for my science class.
But i'm concered that it will melt. How and what should i apply to get rid of my concerns.

2007-03-28 11:01:09 · 1 answers · asked by RiCARD0 1

question: a concave makeup mirror is designed so the virtual image it produces is twice the size of the object when the distance between the object and the mirror is 14 cm. what is the radius of curvature of the mirror?

approach: i took half of do and got 7 cm. then, i plugged in numbers into 1/f = 1/do + 1/di with variables di = 14 cm, do = 7m. I got f = 4.7. I mult. by 2 of that to get radius and got R = 9.4 cm.

Did i read the question right?

2007-03-28 10:54:16 · 1 answers · asked by Jimmy 3

A rescue helicopter lifts a 74 kg person straight up by means of a cable. The person has an upward acceleration of 0.70 m/s^2 and is lifted from rest through a distance of 13 m.

(a) What is the tension in the cable?
(b) How much work is done by the tension in the cable?
(c) How much work is done by the person's weight?
(d) Use the work-energy theorem and find the final speed of the person.

2007-03-28 10:48:30 · 1 answers · asked by vballgyrl45 1

You are a professional witness in a lawsuit. What do you tell the judge? (Read the following scenario.)


You are on an RTD Stretch Bus (the long busses with the accordion in the middle. The bus is fully
loaded with fuel and people. You are traveling at 30 mph when a miniVan pulls in front of the bus as it travels
in a similar direction; the van is traveling 20 mph. The bus driver slams on the brakes, but there is black ice so the bus gracefully slides right into the van sending the van flying ahead. Three passengers, upon realizing their opportunity to make some quick cash, start crying of back and neck pain.

Mass of bus + passengers + fuel is about 66,600 [lb] or 30,200 kg.
Mass of van is about 2,000 kg.

Forensics estimates from the bending of the lightpole that the van was moving at an uninhibited speed of about 35mph when it hit the pole after sliding on ice.

I want to hear what you ideas about this, so please help, and REAL answers...please THANKS

2007-03-28 10:47:40 · 1 answers · asked by Anonymous

the equations: http://i3.tinypic.com/35hqsgk.jpg

2007-03-28 10:43:29 · 1 answers · asked by Anonymous

I have two pieces of glass and when you hold them together it feels like there is a magnetic force pushing the two pieces apart from each other. WHY?

2007-03-28 10:39:08 · 3 answers · asked by jpugh248 1

2007-03-28 10:34:26 · 1 answers · asked by loveiranshiraz 1

2007-03-28 10:09:58 · 5 answers · asked by Alexander 6

A metal sphere has a charge of +6.0 µC. What is the net charge after 6.00 1013 electrons have been placed on it?

2007-03-28 09:55:17 · 1 answers · asked by Alan l 1

i hate this crap!

2007-03-28 09:54:30 · 1 answers · asked by killswitcheng4ge 1

Seems like since you aren't moving that it would.

2007-03-28 09:43:15 · 5 answers · asked by tumbleweed1954 6

2007-03-28 09:42:12 · 4 answers · asked by tonyoseiababio 1

Two bubbles of radius 1 cm each collide and stick together.
Their new shape is two truncated spheres, each of radius R,
resembling digit 8. What is R?

Ignore slight decrease of internal preesure.

2007-03-28 09:40:44 · 1 answers · asked by Alexander 6

If it takes a human cannonball 1.5 s to exit a 1.6 m long cannon, what is the average net force acting on the performer if his mass is 65 kg?

2007-03-28 09:29:33 · 2 answers · asked by Chess 2