Physics - May 2007

i dont understand the question...when is the velocity 0 for an instant while acceleration is not..

2007-05-22 07:41:55 · 2 answers · asked by Kel 1

an engine does 1500J of useful work with each 5000J of energy supplied to it.
what is its efficiency? what happens to the rest of the energy supplied?

2007-05-22 07:24:04 · 6 answers · asked by jessica 1

Pushing a lrg box up a ramp, to overcme the lbs of the box/friction btwn the box and rmp to push bx. Friction force is directed? up? dwn? dwn the ramp? up the ramp? perpendicular to ramp?

2007-05-22 07:18:01 · 1 answers · asked by K W 1

2007-05-22 06:56:26 · 6 answers · asked by kmhusa 1

2007-05-22 06:05:01 · 2 answers · asked by Marilyn M 1

a. regular reflection
b. diffuse reflection
c. refraction
d. diffraction

2007-05-22 06:01:49 · 5 answers · asked by Marilyn M 1

1. Forms of elements that give off matter and energy are called ___________.

2. These elements decay at a fixed rate, this fixed rate is called its __________.

3. This rate can be used to calculate the age of a rock sample in a process
known as _______________________.

4. One element, ____________, has a half-life of 4.5 billion years and so can
be used to date very old rocks.

5. To do this, we measure the ratio of radioactive element remaining to the
amount of transformed element, known as the ________________.

6. For uranium, this transformed element is an element called ____________.

7. Most radioactive dating is done on __________ rock.

8. What is the fraction of a radioactive element left after four half-lives?

9. What is the fraction of an end product would be left after three half-lives?

10. Carbon-14 has a half-life of 5730 years. Uranium has a half-life of 4.5
billion years.

a. Which would be most useful in dating a rock sample 600 mill

2007-05-22 05:11:48 · 6 answers · asked by Anonymous

and through a single pully, rather than just up over the branch of a tree, is that the pully________. A. generates some of the force for you B. changes the pulling direction C. Makes the rope stronger D. Reduces friction. Please Help!!!!!!!!!!!!!!

2007-05-22 05:02:45 · 3 answers · asked by SAM 1

I know that when we look at the stars, we're looking into the past. Since the light that was reflected off the Earth a million years ago had to go somewhere and bounce off something, could we possibly catch that reflection on film?

Since light is made of particles and we see objects because those particles hit objects, is it possible to study that object microscopically and see the impression of the light particles that hit it? If this is possible, might we be able to glimpse into our past?

2007-05-22 04:54:55 · 7 answers · asked by Anonymous

Does the theory of relativity refers to planetary objects or does the quantum theory refers to earthly matters?

2007-05-22 04:04:58 · 5 answers · asked by M 1

anyone with a keen interest like me?

2007-05-22 03:56:19 · 10 answers · asked by jackie n 3

The ray of light strikes the mirror at 48 degrees

2007-05-22 03:50:13 · 11 answers · asked by Anonymous

I was wondering about the following things and wanted the pro-evolution crowd to ponder and answer.
Before you insult and tell me that I do not understand anything, I DO! I used to believe in evolution, but there was ABSOLUTLY no overcoming these objections (at least not in print, that I was able to find, and I DID look).

According to the laws of thermodynamics (and other scientific theorims):
1. Matter cannot be created nor destroyed.
Q1: Where did all existant atomic material come from?
2. ALL things break down, wear out, etc... (the law of entropy)
Q2: Since chaos is the end result of everything, how can evolution account for ordered, non-random, events that created functioning eco-systems and life?
3. a body at rest tends to stay at rest unless acted upon by an OUTSIDE force
Q3: The theory that the universe is expanding from a central point and ALL atomic mass was in a central area, what was the outside force that cause the big bang?

2007-05-22 02:46:44 · 16 answers · asked by athorgarak 4

2007-05-22 02:20:57 · 11 answers · asked by Anonymous

i m gonna do my very first research,,
i have chosen the topic already--
" physics in football ",,(or soccerball)
what could be the areas of research in it??

i have thought of,,finding surface area and volume of my football,,(or soccerball)

anything else??

plss help me as this is my very first research in my life,,

2007-05-22 02:17:34 · 7 answers · asked by gunkedar 2

CASE1--

make tea,(without adding milk)
then quickly pour milk in it,(normal temperature milk)
the temperature of the solution after 10 mins is "x" degree Celsius,

CASE2--
make tea,(without adding milk)
then pour milk in it after 10 mins,(normal temp. milk)
the temperature of the solution is "y" degree Celsius,

question--
which temperature will be hotter,,
"x" or "y"??

pls give me an approx. example,,

2007-05-22 02:06:28 · 7 answers · asked by gunkedar 2

Is it some kind of electromagentic field generated by the user?

2007-05-22 01:46:59 · 5 answers · asked by renolibrado 2

2007-05-22 01:29:02 · 10 answers · asked by Me 3

2007-05-22 01:14:15 · 3 answers · asked by Anonymous

calculate the resultant force of the bone

2007-05-21 22:03:51 · 2 answers · asked by tinyiko g 1

Been trying to work it out and research the net with no results. Could anybody give me a formula to get on the right track please.

2007-05-21 21:50:29 · 13 answers · asked by Stephen J 2

What is the most efficient way to walk up steps under your own power? By efficient I mean creating the least stress on the knee and least muscle exertion. I assume no use of hand rails or walking devices. I have had knee surgery, and have "discovered" two ways of walking up steps. One is the "normal" (plant and lift). The other I couldn't describe, but it has to do with more hinge-ing motion in the knee, and feels less strenuous. This is why I ask the question in these terms. I should think robotics researchers might have considered this, as well as physical therapists.

2007-05-21 21:41:24 · 1 answers · asked by somecards 1

i wish to have a cleare picture what is actually going there .

2007-05-21 21:19:09 · 4 answers · asked by shikha m 1

2007-05-21 20:54:39 · 3 answers · asked by >() 1

if i'm travelling in a train at the speed of light then i wont be able to look at the back of the compartment because those light rays wont reach me and this may prove principal of relativity maybe wrong. but einstein assumes that speed of light is constant for everyone so i'll be able to see the back of the train. i'm just confused over this assumption. how does the light ray reach me? and how does the assumption change this?

2007-05-21 20:50:59 · 3 answers · asked by Anonymous

Lets just assume that pressure doesn't act upon you.

2007-05-21 20:04:55 · 7 answers · asked by Chris tf 2

how does the wave model of light explain the decrease in intensity of the secondary maxima in a single slit diffraction pattern as you move further away from the central maximum of the pattern??

2007-05-21 19:17:10 · 1 answers · asked by c4 2

2007-05-21 19:01:42 · 4 answers · asked by pretty_chi e 1

2007-05-21 18:48:34 · 7 answers · asked by phy2006 1

is it like 6 foot 3 or something? how do you convert 188 cm to the foot and inches?

2007-05-21 18:47:16 · 18 answers · asked by Jose D 1