Physics - February 2007

2007-02-06 20:25:33 · 4 answers · asked by dalman99uk 2

A model of a helicopter rotor has four blades, each of length 3.50 m from the central shaft to the blade tip. The model is rotated in a wind tunnel at a rotational speed of 580 rev/min .

a) What is the linear speed of the blade tip?

_____ m/s

b) What is the radial acceleration of the blade tip expressed as a multiple of the acceleration of gravity, g?

______g

thanks in advance guys!

2007-02-06 19:20:08 · 6 answers · asked by Anonymous

2007-02-06 19:10:48 · 10 answers · asked by Anonymous

What is the new force acting upon the woman?
What is the gravitational force acting upon the woman?
What is the normal force pushing upward on the woman's feet?
Can someone check my answers? I got 0 N, 588N, and 516 N

2007-02-06 18:44:23 · 4 answers · asked by M^3 1

2007-02-06 18:42:03 · 2 answers · asked by M^3 1

If you had the ability to stick to any surface securely at any point of contact and you also have quick locomotive ability and you had to descend on an extremely steep slope, which would be faster, climbing down with sticky hands and feets or simply running down on the slope?

2007-02-06 18:16:57 · 1 answers · asked by digi_day_dreamer@sbcglobal.net 2

A student tries to observe a coin in an empty basin.The student cannot see the coin in the empty basin,but he can see the coin when the basin is filled almost to the brim with water.

a)Make one suitable observation

b)State a hypothesis that could be investigated

c)The aim of the experiment
d)Variables of the experiment

e)The procedure of the experiment which includes the method of controlling the manipulated variable and the method of measuring the responding variable

f)Conclusion

g)Precausion

Choose one or if you're really smart you can try all.

2007-02-06 17:36:31 · 3 answers · asked by blah,blah,blah 3

We can assume spacetime as being a flexible multi-layered trampoline,or a volume of some fluid,is'nt it?If this is true,then there is a CERTAIN amount of spacetime(in the universe)at a FIXED time,although this amount is tremendously large,which is why we SAY it to be limitless of infinite,as we will never be able to determine this CERTAIN amount.(I use the word FIXED as Hubble's Law says, universe is ever-increasing.)If this were true,we could say that spacetime is conserved at a PARTICULAR INSTANT OF TIME.So,my 1st question is that,could there be A LAW OF CONSERVATION OF SPACETIME?

If such a law could could be framed,then what it would suggest is that when a black hole is being formed,there should be a simultaneous formation of an 'anti-black hole' in order to keep spacetime conserved in all the infinitesimal time intervals during its formation.So,my 2nd question,which is a direct consequence of the 1st question,is that could there be anti-black holes, which we have not detected?

2007-02-06 17:28:52 · 8 answers · asked by Kristada 2

A block of mass 2.5kg is pushed 2.20m along a frictionless horizontal table by a constant 16.0 N force directed 25.0 degrees below the horizontal. Determine the work done by (a) the applied force, (b) the normal force exerted by the table, (c) the force of gravity and (d) the net force on the block.

2007-02-06 17:20:08 · 3 answers · asked by portraitofsound 1

Hi, I'm stuck on this problem:

A space shuttle orbits earth in a near-circular orbit at a constant speed approximately 100 miles above the Earth's surface.
If we assume that the centripetal acceleration is equal to the acceleration due to gravity at sea level (9.8 m/s^2) and the orbital radius is equal to the radius of the Earth (6380 km):

a) what is the average speed of the shuttle?
b) How long does it take the shuttle to make one orbit around earth?

I'm specifically having problems w/ the wording on the first sentence, is 100m the speed of the shuttle or is it the distance above earth?
is it:
...at a constant speed 100 miles, above the earth's surface...
or
...at a constant speed, 100 miles above the earth's surface.

- in any case how would i go about solving it?

2007-02-06 17:00:22 · 3 answers · asked by Anonymous

A and B begin,at 6 a.m. on the same day, to walk along a road in the same direction, B having a start of 14 kilometers and each walking from 6 a.m. to 6 p.m. daily. A walks 10 kilometers, at a uniform pace, the first day, 9 the second, 8 the third, and so on. B walks 2 kilometers, at a uniform pace, the first day, 4 the second, 6 the third, and so on. When and where are they together?

2007-02-06 16:45:21 · 2 answers · asked by eschellmann2000 4

why is the lenght of a wire used in metre bridge kept between 25 to 75?
A METRE BRIDGE is a device to measure the resistance of a given wire.

2007-02-06 16:36:51 · 6 answers · asked by jubin s 1

(If you are a blond female than do not even bother answering this question.)

2007-02-06 16:35:46 · 7 answers · asked by jaggy_233 1

2007-02-06 16:26:16 · 4 answers · asked by lao 1

A simple 2.00m-long pendulum oscillates in a location where g =9.8. How many complete oscillations does it make in 5. minutes?
I use the formula and find T, then I divide it by whatever I got. but I don't get the answer. The answer is 105 oscillations. What am I doing wrong?

2007-02-06 15:49:13 · 2 answers · asked by Anaksonamun 2

the creams does not start to freeze until you add salt. on myth busters the temp of ice went blow freezing when salt was added as compared to when salt was not added to ice

2007-02-06 15:44:16 · 4 answers · asked by Anonymous

Ok I'm taking this physics problem but is driving me insane. here it is

Using a Diagram that you can view in: http://besaid.us/diagram.jpg

A bead of mass m = 5kg is release from point A and slides on the frictionless track shown in diagram. Determine (a) the bead's speed at points B and C and (b) the net work done by the force of gravity in moving the bead from A to C.

I've been trying crazy to figure out this problem but I seriously I don't have a single idea. If you can help me by showing me how it is solved with the work progress I would gladly apprecieate it. Thanks!

2007-02-06 15:32:27 · 2 answers · asked by .joel 2

1. human beings will never set foot on the moon. 2. some of the laws that govern nature cannot be detected by scientists. 3. it is quite possible that in some other galaxy the laws of physics are fundamentally different than the laws we are acquainted with in the galaxy. 4. none of the above statements are correct.

please explain your answer.

2007-02-06 15:26:46 · 1 answers · asked by Ted g 1

2007-02-06 15:21:57 · 8 answers · asked by Anonymous

Given that a mirror needs light to work.

2007-02-06 15:21:03 · 10 answers · asked by Smo 4

Here are some problems that I am having problems with:

1) In a car lift used in a service station, compressed air exerts a force on a small piston of circular cross-section having a radius of 3.84 cm. This presure is transmitted by a liqud to a second piston of radius 24.1 cm. What force must the compressed air exert in order to lift a car weighing 11500 N? answer in N

2) What air pressure will produce this force? answer in units of Pa

3) Assume the density of sea water is 1024 kg/m^3 and take the atmostpheric pressure equal to 101000 Pa.
The acceleration of gravity is 9.8 m/s^2. Calculate the pressure at an ocean depth of 1240m. Answer in unts of Pa.

4) Calculate the total force exerted on teh outside of a circular sbmarine window of a diameter 43.7 cm at this depth. answer in uits of N.


Thank you for any help!

2007-02-06 15:08:49 · 1 answers · asked by Cool_Tall_One 3

A visitor to a lighthouse wishes to determine the height of the tower. She ties a spool of thread to a small rock to make a simple pendulum, which she hangs down the center of a spiral staircase of the tower.The period of oscillation is 9.40s. What is the height of the tower?

2007-02-06 15:06:14 · 2 answers · asked by Kitana 2

2007-02-06 14:47:18 · 3 answers · asked by Anonymous

The Z axis is perpendicular to the washer plane, so when looking head on at the washer the X axis is left and right.

2007-02-06 14:46:31 · 1 answers · asked by Anonymous

2007-02-06 14:41:34 · 6 answers · asked by Anonymous

1/2mr0^2 + 1/2mri^2 = Inertia of the ring. Why is it plus and not negative? the intergral should be subtraction. no?

Thanks

2007-02-06 14:25:06 · 1 answers · asked by Anonymous

Quantum information states the electron does not orbit the nucleus but instead vibrates in some wave propagation, yet definitions of the number of electron orbits per second exist.. While certainly vibration and wave propagtion are factors, the cyclic motion of rotation and orbit must begin at atomic levels but where and is there a base value of reference? There are various measurements defined which should allow some calculation of this but the definitions when cross-compared are conflicting.

Electron orbits per second = about 6.5 trillion times per second
Speed of an electron in hydrogen = 220,000,000 cm per second
Hydrogen Radius = 5,292,000,000th of a centimeter.
Light travels radius of hydrogen atom = 10 to -18th power/second.
Light travels 1 foot (30.48 cm) = 1,000,000,000th of a second (ns)

By these definitions the electron orbit should be more per second than defined and the speed of light appears not constant in moving from the hydrogen atom outward to 1 foot.

2007-02-06 14:24:34 · 1 answers · asked by alchemaniacal 1

If photons are the means of transferrence of forces between particles and photons can knock out an electron (photoelectric effect) than how is it an attractive force rather than a repulsive force in atoms?

2007-02-06 14:18:49 · 3 answers · asked by Twizard113 5

so i don't see how the distance from the earth to the moon relates to finding the mass of the earth. other info given is that the radius of the earth is 6.38x10^6 meters, radius of the moon is 1.74x10^6 meters, mass of the earth is 5.98x10^24 kilogram, and mass of the moon is 7.4x10^22 kg, and the universal graviatity constant is -6.67x10^-11 Nm^2/kg^2

2007-02-06 14:13:10 · 1 answers · asked by clock 2

2007-02-06 14:11:38 · 6 answers · asked by Anonymous