Physics - August 2007

Ok, ok. All you budding Quantum Physicists are welcome to weigh in as well.

Quickly, briefly, summarily explain the difference between Loop Quantum Gravity Theory and Superstring Theory (in it's direct correlation to LQG). Which you subscribe to, and why it is better than the opposing theory.

2007-08-30 16:47:03 · 6 answers · asked by Anonymous

2007-08-30 16:45:22 · 3 answers · asked by darlingpinkashley 1

2007-08-30 16:40:58 · 12 answers · asked by Anonymous

A dragster starts from rest and accelerates down the track. Each tire has a radius of 0.320 m and rolls without slipping. At a distance of 374 m, the angular speed of the wheels is 276 rad/s.
What is the algebraic expression for the magnitude α of the angular acceleration of the dragster's wheels? Express your answer in terms of the dragster's initial and final linear speeds, v0 and v, the distance x it travels, and the radius r of a wheel.

2007-08-30 16:32:28 · 2 answers · asked by Anonymous

Two identical dragsters, starting from rest, accelerate side-by-side along a straight track. The wheels on one of the cars roll without slipping, while the wheels on the other slip during part of the time.
For the dragster whose wheels roll without slipping, is there a relationship between the magnitude a (in m/s2) of its linear acceleration and the magnitude α (in rad/s2) of the angular acceleration of its wheels?
a) Yes. The relationship is a= alpha^2 / r, where r (in m) is the radius of a wheel.
b) Yes. The relationship is alpha= ra, where r (in m) is the radius of a wheel.
c) no
d) Yes. The relationship is a= r alpha, where r (in m) is the radius of a wheel.

2007-08-30 16:30:40 · 1 answers · asked by Anonymous

Two identical dragsters, starting from rest, accelerate side-by-side along a straight track. The wheels on one of the cars roll without slipping, while the wheels on the other slip during part of the time.
For the dragster whose wheels roll without slipping, is there a relationship between its linear speed v (in m/s) and the angular speed ω (in rad/s) of its wheels?
a) Yes. The relationship is V=r w , where r (in m) is the radius of a wheel.
b) No
c) Yes. The relationship is w=r v , where r (in m) is the radius of a wheel.
d) Yes. The relationship is w=v^2 / r, where r (in m) is the radius of a wheel.

2007-08-30 16:27:24 · 1 answers · asked by Anonymous

Which consumes more power (watts) the office worker or a 100 - W light bulb.

2007-08-30 16:26:01 · 2 answers · asked by webogirl 2

Two identical dragsters, starting from rest, accelerate side-by-side along a straight track. The wheels on one of the cars roll without slipping, while the wheels on the other slip during part of the time.
For which car, the winner or the loser, do the wheels roll without slipping?
a) Both dragsters reach the finish line at the same time.
b) the winner
c) the loser

2007-08-30 16:23:40 · 1 answers · asked by wake up 1

when shooting and arrow than the string in bow B. Which bow gives its arrow a greater acceleration? Or, do neither give their arrow acceleration?

2007-08-30 15:53:48 · 3 answers · asked by Diff 1

please see the link for question

http://answerboard.cramster.com/physics-topic-5-94227-0.aspx

2007-08-30 15:49:54 · 1 answers · asked by wake up 1

I have V takeoff=134 m/s, t takeoff=26.83,
A plane accelerates from rest at a constant rate of 5.00 meters/ seconds squared along a runway that is 1800M long. Assume that the plane reaches the required takeoff velocity at the end of the runway.

2007-08-30 15:45:35 · 3 answers · asked by osu9295 1

All input is greatly appreciated! =)

2007-08-30 15:17:05 · 11 answers · asked by xplozno8 2

So i have this huge assignment due and i have been working on it for 3 days and there are 3 questions on the thing i just cant get. i dont know if its just because i have been looking at for so long or what but please help.
1- an object with a of mass of 2.12kg is attached to a string to be used as a pendulum. The object is raised above its initial position so that its potential energy is 3.74 J higher than when the object is in its lowest position. The object is released and begins to move. How fast is the object moving when it gets back to its lowest position?

2-Describe the energy conversions for the process that begins at a power plant and eventually turns a ceiling fan.

3- describe energy conversions for the process that begins when a person eats food and ending with that person running.

Please help me. Any help will be appriciated. If you know #1 can you also let me know the work/ equation used to get the answer so i understand it thanks.

2007-08-30 15:10:36 · 1 answers · asked by DP 3

IMA = 1/sin(a)

I have a at 20 degree + or minus 0.5 degree.

How do I calculate the uncertainty of IMA ?

2007-08-30 15:04:15 · 2 answers · asked by confusing 1

2007-08-30 14:58:54 · 3 answers · asked by rona_912 2

I want to do this with the "Unit Conversion" method. A vehicle is traveling 15 kmh, how long does it take to go 100 meters in seconds. (I know 15000x=3600(100) x=24s....that's not the question)

I want to know how to do it with "Unit Conversion" method where all the unwanted units cancel out.
i.e.
15km/hr *1000m/Km *hr/3600s ...

I need to set up the fractions in such a way to end up with 100m/24s without having to do anything else. Maybe 100 meters needs to be paired with something else?

2007-08-30 14:56:51 · 3 answers · asked by RogerDodger 1

A ball is dropped from rest from a height h above the ground. Another ball is thrown vertically upwards from the ground at the instant the first ball is released. Determine the speed of the second ball if the two balls are to meet at a height h/3 above the ground.

Details please!!!

2007-08-30 14:56:12 · 1 answers · asked by Anonymous

Ok Im new to electricity with physics and I cant figure out what I did wrong.

A particle of mass 60 g and charge 20 uC released from rest when its 60 cm from a particle of charge -15 uC
What is the magnitude of initial acceleration of the 64 g particle? (m/s^2)

OK a = kqq/(mass * r^2)

So (2.0e-5 * -1.5e-5 * 8.99e9)/(.064kg * .60^2) = -102.88

Just came to a revalation is this really the equation
a = kqq/r^2 * mass?
with an answer of -.479

2007-08-30 14:51:44 · 1 answers · asked by sotkinghunter 1

A 2.2µC point charge is placed in an external uniform electric field of 1.62x104 N/C. At what distance from the charge is the net electric field zero?

2007-08-30 14:51:20 · 2 answers · asked by Anonymous

A small sphere with a charge of -6.0 10-7 C is placed in a uniform electric field of magnitude 1.2 106 N/C pointing to the west. What is the magnitude and direction of the force on the sphere due to the electric field?

2007-08-30 14:50:05 · 2 answers · asked by Anonymous

2007-08-30 14:47:18 · 7 answers · asked by TwiggyRamirez 2

A truck covers 45.0 m in 8.00 s while smoothly slowing down to final speed +2.00 m/s.
a. Find its original speed in m/s
b. Find its acceleration in m/s2

2007-08-30 14:46:39 · 2 answers · asked by Anonymous

shooting an arrow than the string in bow B. Which bow gives its arrow a greater acceleration? Explain.

2007-08-30 14:44:47 · 2 answers · asked by Diff 1

I really need help with this question...

A railway carriage of mass 3.5 x 10^3kg is moving at 4.0m/s on a straight,horizontal track. It collides with a stationary carriage on the same track. As a result of the collision, the two carriages become linked together and move at 2.5m/s. Calculate the mass of the second carriage.

2007-08-30 14:44:03 · 2 answers · asked by Anonymous

Okay, well, I was assigned a problem on how to solve for instantaneous velocity and I don't know how to do it. I'm in AP Calculus based Physics.

I'm not asking for answers. I just want to know how to get it. I already have the answers but I need to know how to get to that stage.

It goes like this:

The position of a particle moving along the x-axis is given in centimeters by x=9.75+1.50t^3. Consider the time interval between 2 seconds and 3 seconds and calculate (a) the average velocity, (b) the instantaneous velocity at 2s, (c) the instantaneous velocity at 3s, (d) the instantaneous velocity at 2.5s, and the instananeous velocity when the particle is midway between its positions at t=2s and t=3s.

Would you use a limit function? Or dv/dt?

If you use either, how would you solve it?

2007-08-30 14:28:23 · 2 answers · asked by Betty 3

What is the instantaneous speed (in m/s) at the 10-second mark for a car that accelerates at 2 m/s squared from a position of rest? I need the answer, but I need a very very very easy to understand explanation for how you got the answer. Thank you.

2007-08-30 14:03:53 · 2 answers · asked by Anonymous

in a filament lamp circuit as the voltage reached a certain high level and the circuit behaved not according to ohm's law. Can you give me a reason why?

2007-08-30 14:02:54 · 5 answers · asked by Anonymous

i see lots of people going down the rainbow river in thunder and lightning storms. I know they should get off the river, but they don't. So I would really like to know what would happen if lightning struke near them.

2007-08-30 13:43:29 · 7 answers · asked by Anonymous

And what is the distance (in km) that he runs if he maintains this average speed for 1 hour? I need the answer, but I also need a very very easy to understand explanation for the answer. Thank you.

2007-08-30 13:38:39 · 2 answers · asked by Anonymous

I am doing some physics work and I am confused about a certain question. It is as follows:

The dot product of two vectors
1. is a scalar
2. is 0 if the two vectors are perpendicular
3. lies perpendicular to the plane defined by the two vectors

and I have to state which statements are true. It can be 1 only, 2 only, 3 only, 1 and 2 only, or all three.

As of right now I am pretty sure that 1 and 2 are true, but I am not sure about 3. Can anyone tell me which ones are true, and if possible, explain to my why? (i am just beginning my physics studies and I find it difficult. By the way does anyone know any good websites or books that can break down this sort of thing as my textbook is kind of advanced.)

2007-08-30 13:30:48 · 1 answers · asked by Mark the man 2