Physics - April 2007

Can anyone please help me to answer this question:

How can the ability to pentrate matter be used to distingushed between alpha beta and gama rdiation?

Thanks

2007-04-30 04:15:58 · 2 answers · asked by prodyutghosh 2

2007-04-30 03:45:48 · 5 answers · asked by . 6

i have to make a project and need to show the use of windowsof alternate shapes in aircrafts

2007-04-30 02:11:21 · 9 answers · asked by dev 1

If you've got a Stapler with you, pick it up and examine the part of the device that folds the staple inwards. if you turn the Stapler over, you'll see that there is facillity to turn this part of the device around 180degrees on its axis. This then makes the staples fold outwards instead of inwards. That's all very well, but why in the world would you be wanting to do it that way? Almost every Stapler has this facillity. I really can't imagine what benifit is to be gained.

2007-04-30 01:03:11 · 9 answers · asked by kriswhoosh 1

1) Suppose you are standing by the side of a road in the Sahara desert where the temperature has reached a hot 55.4 oC (132 oF). A truck, traveling at constant speed, passes by. After 3.53 s have elapsed, you use the ultrasonic ruler discussed in Example 4 to measure the distance to the truck. A sound pulse leaves the ultrsonic ruler and returns 1.29 s later. Assume that the average molecular mass of air is 28.9 u, air is an ideal diatomic gas ( = 7/5), and the truck moves a negligible distance in the time it takes for the sound pulse to reach it. Determine how fast the truck is moving.
2)An irreversible engine operates between temperatures of TH = 877 K and TC = 307 K. It absorbs 1270 J of heat from the hot reservoir and does 213 J of work. If the engine were reversible, what is the magnitude |Wreversible| of the work it would have done, assuming it operated between the same temperatures and absorbed the same heat as the irreversible engine?

2007-04-30 00:28:57 · 1 answers · asked by Hilary R 1

If the motion of a particle is defined by:
x = 7t^2 + 6t +9 and
y = 6t^3 -9
where x and y are in m, and t is in secs

what is the component of acclereation in the tangetial direction when t=2.0s??

From what i understand,
dx/dt= 14 and dy/dt= 36t. If i substitute t= 2.0 in both these equations, and find the magnitude of this, then a= 73.34m/s^2... How do i find the acceleration in the TANGETIAL direction though..

Help please,
many thanks

2007-04-29 22:02:34 · 2 answers · asked by ivan a 1

in a experiment 200kg of aluminium (c=880 J/kgC0 at 100C is dropped into 256kg of kerosene at 15C. the mixture reaches a temperature of 50C. what is the specific heat of kerosene? show working out

2007-04-29 21:43:05 · 1 answers · asked by moonlight123 1

how do u know if a colllison is elastic?
is the collision elastic if final velocity of a object is after collison is 0.075m/s of a and b rebounds with a speed of 0.10m/s

2007-04-29 21:38:46 · 1 answers · asked by moonlight123 1

a light plank(weightis assumed negligible)10.0m long is projecting over the edge of a building with 2.0m of its length protuding. how far out along the protruding part can a person of mass 124kg walk before the beam titlts, if there is an object of mass 18kg on the other end of the plank. show working out

2007-04-29 21:34:35 · 2 answers · asked by moonlight123 1

how generator can produce an ac current when motor inside generator cutting the magnetic field around it

2007-04-29 19:48:30 · 3 answers · asked by Nov 1

A kilowatt hour is the unit of power that an electric current company charges for electrcity. One kilowatt-hour is equal to how many joules?

~Please help!!

2007-04-29 19:03:12 · 5 answers · asked by Cheyenne 2

can somebody please help explain what this equation is. i have to do a report on einstein theory for math and i don't know what this means. i tried researching it but could come up with a correct answer. i am in the 8th grade so can you please not use really big words and explain it.

2007-04-29 18:40:55 · 7 answers · asked by Gill 2

eyglasses or contacts are used to correct the focal point of the light entering the eye (the focal point misses the retina in a nearsighterd person)so that this focal point is right on the retina where it can be seen.

2007-04-29 18:40:19 · 3 answers · asked by myke_n_ykes 6

2007-04-29 18:16:58 · 2 answers · asked by myke_n_ykes 6

A 12kg uniform board is wedged into a corner & held by a spring at a 55 deg angle. Bond length= 50 cm. spring constant is 180 N/m and is parallel to the floor.
a) What is the torque due to the weight
b) find the amount at which the spring is stretched from its unrestrained length
c)magnitude of the force exerted on the borded by the corner at the wedge

2007-04-29 17:21:35 · 1 answers · asked by Anonymous

A hockey puck is set in motion across a frozen pond. If ice friction and air resistance are neglected, the force required to keep the puck sliding at constant velocity is:

A. 0 N
B. equal to the weight of the puck
C. the weight of the puck divided by the mass of the puck
D. none of these

2007-04-29 17:21:32 · 2 answers · asked by Mo 1

A small ball rolls off the edge of a tabletop that is 1.20m high. It strikes the floor at a point 1.52m horizontally from the table edge. a)how long is the ball in the air? b) what is its speed at the instant it leaves the table?

2007-04-29 17:11:42 · 2 answers · asked by Anonymous

If the force acting on a cart doubles, what happens to the cart's acceleration?

A. it doubles
B. it halves
C. it quarters
D. it stays the same

2007-04-29 17:04:56 · 7 answers · asked by Anonymous

2007-04-29 16:32:09 · 3 answers · asked by myke_n_ykes 6

Now, I am not a mathmatician, and I cant even balance my check book, however, when I was younger in 1976, the basic fundamental expansion and contraction periods or oscillations of this planet was, in those terms, aprox. 7.0477 hertz and/or cycles per linear second.
where t=sec. f=frequency and Wl=wavelength in meters and of course, c=300,000 meters-sec or 186,282.5 miles per second.
(humm, I wonder how many cupids are in a lightsecond).
Well...back then, in the early seventies, the new-age of enlightenment was beginning, and the Alpha and theta brainwaves of the master yogas,gurus, mystics, krishnas, Jane roberts, and trancendental medititationists,...were being measured at 7.0 to 12.0
hertz or cycles per second, aka the alpha awareness state of effortless concentration and awareness, aka silva mind control method, etc. yada, yada yoda, luke,lea..anyway, the question is
Why are these frequencies of the earth slowly increasing? Perhaps the transformation of earth is true? 2011AD?

2007-04-29 16:30:22 · 2 answers · asked by rdmlawsky147 1

2007-04-29 16:22:37 · 9 answers · asked by Anonymous

A 2 kg mass is dropped from a height of 2 meters. What is its acceleration as it falls towards Earth?

and also, what is its weight?

2007-04-29 16:09:13 · 2 answers · asked by Anonymous

Calculate the work that had to be done by the external force to bring Q to the origin from the distant point if there is a force of 3.13 x 10^-48 opposing it

2007-04-29 15:57:11 · 1 answers · asked by Timmy boy 1

We did a lab on electricity and resistors and such. Here are the results:
V (V) I (A)
1.5 0.12
3.0 0.25
5.0 0.43
6.0 0.50
9.0 0.78
10.0 0.82
we were asked to graph this.. from the info was the resistor on to full? and what's the slope..also what's the relationship of potential difference and current (according ot the data)
what was the resistance of this resistor? thanks!

2007-04-29 14:15:06 · 2 answers · asked by Besch 4

what is the units for momentum? is it kg*m/s?

2007-04-29 14:14:42 · 3 answers · asked by Anonymous

...the puppy?

My wife says it could have; I say the puppy just would have been slightly and temporarily injured (assuming, of course, that the lid stayed on the bleach and no bleach leaked out).

Best physics-based answers, please....

2007-04-29 14:09:09 · 2 answers · asked by Skepticat 6

Can anyone explain the operation of the rotating coil and tell me where I can find some diagrams showing the rotating coil in various operations? Also, can anyone explain how the worlds simplest motor can be used as an electric generator?

2007-04-29 14:01:11 · 1 answers · asked by J M 1

When I strike a tuning fork in the physics lab cut to vibrate at the sound of middle c on a piano, it vibrates or oscillates at
256 hertz.
If I cut a number of brass tubes to variable lengths, like wind chimes, then the shorter ones vibrate faster per second than the longer ones. So. In those terms, and viewing the earth as a giant tuning fork or sphere,...what is the basic and fundamental (note) or frequency, or wavelength of this planet?
Serious replies only if you dont mind, thank you.

2007-04-29 12:20:28 · 2 answers · asked by rdmlawsky147 1

A block is on a horizontal surface (a shake table) that is moving back and forth horizontally with simple harmonic motion of frequency 3.2 Hz. The coefficient of static friction between block and surface is 0.40. How great can the amplitude of the SHM be if the block is not to slip along the surface?

2007-04-29 12:05:26 · 1 answers · asked by Anonymous

A rifle bullet with mass 8g strikes and embeds itself in a block with mass .992kg that rests on a frictionless, horizontal surface and is attached to a coil spring. the impact compresses the spring 15cm. calibration of the spring shows that a force of .750N is required to compress the spring.250cm.
a) find the magnitude of the block's velocity just after impact.
b) what is the initial speed of the bullet?

2007-04-29 11:57:02 · 1 answers · asked by smiley25 2