Physics - June 2007

At a given instant, the blood pressure in the heart is 1.90 104 Pa. If an artery in the brain is 0.50 m above the heart, what is the pressure in the artery? Ignore any pressure changes due to blood flow.

1060 which formula would i use since its in pascals?

2007-06-19 16:22:13 · 1 answers · asked by wildcherrychica1 2

The filament of a light bulb has a temperature of 3.00 103 °C and radiates 51 watts of power. The emissivity of the filament is 0.35. Find the surface area of the filament.

only one equation for radiation that i know off and it doesn't work for this type of problem

2007-06-19 16:07:54 · 1 answers · asked by gayle w 1

Hi. I'm not a beginner in Physics and I have a good understanding of work/ energy.
but this confuses me:


When I push an object directly upwards, the work I do is obviously mgh. BUt when I push an object up and at angle not = 90 degrees, (I KNOW the work done is ALSO mgh) but it confuses me how I get there. )
Wouldn't the work done have to be equal to the force (in the direction I'm pushing) * distance this force (which is at an angle) acts?
Why does mgh work when h just accounts for the vertical displacement and not the horizontal component.
I understand that an energy transformation is taking place, and Ep is increasing obviously...but if I push at a constant speed at an angle upwards, that means mg is balanced with the Normal force and Applied force y components right? but then isn't there a horizontal component that is a force and a horizontal displacement obviously , so what about this work??

Can someone explain a definition of work that would work for all cases ?

2007-06-19 15:51:15 · 5 answers · asked by Anonymous

According to Einstein, time is not constant, but can be manipulated. For instance, something in a state of motion moves forward through time quicker than something in a state of rest (though the something in a state of rest is still moving forward in time). Thus said, is it not possible that there must be some sort of constant for the something in a state of rest, some number, that could be used to figure out how much faster something in a state of motion goes forward in time? If so, how would it be possible to find that constant number for the state of rest? Thank you! :)

2007-06-19 15:42:49 · 3 answers · asked by cadence_lost 3

A dentist's chair with a patient in it weighs 2520 N. The output plunger of a hydraulic system begins to lift the chair when the dentist's foot applies a force of 48 N to the input piston. Neglect any height difference between the plunger and the piston. What is the ratio of the radius of the plunger to the radius of the piston?
rplunger / rpiston =

I know that p2=p1+pgh and p2=p1
need help in solving it i manipulated the formulas and most of the variables cancel out but the result is wrong

2007-06-19 15:36:24 · 1 answers · asked by wildcherrychica1 2

2007-06-19 15:35:06 · 1 answers · asked by Anant 2

Hi everyone, I wonder if there was a God who created the Universe? And what God was this? What did he look like? The Universe is so big and vast, but how did it come about? Who created it? Why is there the Universe like it is? Did the Universe start from the size of the pin of the needle? How could you imagine the Universe really start such size? The Universe started from a Big Bang? But what nature or force started the Big Bang? Is there new Universe being formed? If there was a God who created the Universe, then is it possible that he is still alive? What planet is he in now? Look like there are a vast number of planets and they are real and physical, so did the Universe start from nothing?

2007-06-19 15:32:30 · 6 answers · asked by Anonymous

can someone check these questions for me? I

1. If a car moves with a constant velocity, it also moves with a constant speed because constant velocity means motion in a straight line in a constant speed.

2. The acceleration of a car that maintains a constant velocity of 100 km/h for 10s is

[Acceleration = change in velocity/time interval]
[Acceleration = 100km/h / 10s= 10km/hs]

The answer is 10km/hs

3. An object cannot reverse its direction of travel while maintaining a constant acceleration because we can change the velocity of an object by changing its direction; changes in velocity of an object will lead to changes in acceleration. Therefore, whenever the direction changes, both the velocity and the acceleration also change. For example, though a car is moving in a constant speed, its velocity changes when it u-turns.

4: If the net force acting on a sliding block is somehow tripled, by how much does the acceleration increase?

It’ll have three times as much acceleration

2007-06-19 14:32:37 · 6 answers · asked by Anonymous

can you please help me on manipulating formulas?or give me some sites that could help perhaps?

2007-06-19 14:14:21 · 2 answers · asked by skyErrSkEe 1

Everyone seems to think there car is unbeatable but is it true you can only spin or go but so fast..

2007-06-19 13:54:52 · 2 answers · asked by Akirah S 1

Two ice skaters approach each other at right angles. skater A has a mass of 38. 6 kg and travels +x direction at 2m/s. Skater B has a mass of 73.7 kg and is moving in the +y direction at 0.963m/s. They collide and cling together. Find the final speed of the couple.

I got 12.17 m/s but I dont know if I am correct

2007-06-19 13:34:39 · 2 answers · asked by Anonymous

Just wondering on the comments and discussions of this topic.

2007-06-19 13:24:20 · 17 answers · asked by John 4

a. positive ion
b. negative ion
c. nucleus
d. superconductor

2007-06-19 12:38:49 · 6 answers · asked by Anonymous

The specifications are, Assuming a designers requires a motor veichle to accelerate its 670mm diamater drive wheels from a standing start to 40rads/sec in 6 seconds. If the mass is 1500kg the friction coefficient between road and tyres is 0.35 and taking its acceleration due t gravity as 10m/s/s.

Help with these question:
1) The angular acceleration of the wheels to attain cruising speed.
2)The forward velocity of the veichle when up to cruising speed.
3) The distance travelled to attain this speed.
4) The total load required to be produced by the engine.
5) The power developed by the engine in getting up to speed.

Thanks, full points given to the best.

2007-06-19 12:20:35 · 2 answers · asked by fanta m 1

2007-06-19 11:44:24 · 7 answers · asked by Alexander 6

2007-06-19 11:36:50 · 1 answers · asked by Koby J 1

2007-06-19 11:21:10 · 2 answers · asked by Alexander 6

.
http://www.maniacworld.com/water-at-triple-point.html
.
.

2007-06-19 11:18:13 · 5 answers · asked by ? 5

While studying Physics we are taught that nothing can exceed the speed at which light travels. Why is this so ? Why do the laws of Physics consider it a limiting factor ? Should not the maximum possible speed for an object be infinite ? ( Please answer in lay man's language as I am a non science student, thanks )

2007-06-19 11:02:12 · 22 answers · asked by bruce_wayne 2

2007-06-19 11:00:06 · 22 answers · asked by tony p 1

2007-06-19 10:59:03 · 9 answers · asked by Anonymous

A woman finds the front windshield of her car covered with ice at -12.8°C. The ice has a thickness of 4.60 10-4 m, and the windshield has an area of 1.25 m2. The density of ice is 917 kg/m3. How much heat is required to melt the ice?

this problem is listed as easy, but I'm stuck have no idea how to do it. I know you should use the formula Q=mL or change temp=Q/constant*mass<

2007-06-19 10:51:36 · 5 answers · asked by wildcherrychica1 2

2007-06-19 10:39:14 · 2 answers · asked by Rendell T 1

The non-conservative force propelling a 1500kg car up a
mountain does 4700000 J of work on the car. The car starts from rest at sea level and has a speed of 27m/s at 200 m above sea level. Obtain the work done on the car by the combined forces of ar resistance and friction, both of which are nonconservative forces.

2007-06-19 10:10:15 · 1 answers · asked by Anonymous

A crate of mass m1 on a frictionless inclined plane is attached to another crate of mass m2 by a massless rope. The rope passes over an ideal pulley so the mass m2 is suspended in air. The plane is inclined at an angle = 36.9°. Use conservation of energy to find how fast crate m2 is moving after m1 has traveled a distance of 1.4 m along the incline, starting from rest. The mass of m1 is 10.4 kg and the mass of m2 is 12.5 kg

2007-06-19 09:42:30 · 1 answers · asked by terra_flare_aqua_ciel 1

What is the temperature of a body ?

" The temperature of a system is defined as simply the average energy of microscopic motions of a single particle in the system per degree of freedom. For an ideal monatomic gas, the microscopic motions are the translational motions of the constituent gas particles. "

So, if the temperature is a measure dependant on average kinetic energy, will it be frame dependant like kinetic energy ?

To illustrate, consider a closed massless container filler with an ideal mono-atomic inert gas. Let is also be rest with any frame of referance A. According to the kinetic theory of gasses, the molecules inside the gas will experience random motion in all directions. This will contribute to heat and in turn temperature. Since there is no external force acting on this adiabatic and closed system, its center of mass be at rest.

2007-06-19 09:14:05 · 7 answers · asked by Anonymous

a scuba diver is below the surface of the water when a storm approaches, dropping the air pressure above the water. would a sufficiently sensitive pressure gauge attached to his wrist register this drop in air pressure? Give your reasoning assuming that the diver's wrist does not move as the storm approaches.

I was going to say no because if the scuba diver is that far down in the ocean, he would not feel the drop in air pressure due to all the water pressure on top of him...is this wrong?

2007-06-19 08:59:44 · 4 answers · asked by Kel 1

A is the unit of Current

2007-06-19 08:53:04 · 3 answers · asked by Anonymous

E.g. how to turn a thermal gradient into an electric potential difference? (Best without going through mechanical energy)

2007-06-19 08:45:01 · 4 answers · asked by jarynth2 2

Two identical containers are open at the top and are connected at the bottom via a tube of negligible volume and a valve which is closed. Both containers are filled initially to the same height of 1.00 m, one with water, the other with mercury, as the drawing indicates. The valve is then opened. Water and mercury are immiscible. Determine the fluid level in the left container when equilibrium is reestablished.
distance from the bottom

Keep getting the wrong solution even though I did it using the formula my teacher told me to use. Can you help me find my error?

PwgH=PHggh
Pwh=PHgh
(1.0043)(9.8)=13600h(9.8)
x=1-h
got the answer to be 1.9265<

2007-06-19 07:59:35 · 4 answers · asked by wildcherrychica1 2