Physics - February 2007

2.5 m/s. The coefficient of kinetic friction is 0.06. Find the motor power required if the mass of the average skier is 85 kg.

2007-02-20 11:21:38 · 1 answers · asked by Anonymous

2007-02-20 11:21:13 · 1 answers · asked by Anonymous

We are learning about them in English class(?). Amazing the extents of modern education... Details, please! =)

2007-02-20 11:13:26 · 4 answers · asked by Anonymous

2007-02-20 11:11:45 · 2 answers · asked by don't_worry_about_it 1

If 100m of telephone wire is suspended between two poles separated by 95m and a pelican (m=5kg) lands midway along the wire, what is the tension in the wire due to the bird?

I'm having trouble setting this one up. My book does not give very many tension examples so unfortunately I do not have any models to go by.

2007-02-20 10:53:05 · 2 answers · asked by ellyvstheworld 1

This is not a problem that I need help with. I rambled on and on for 5 minutes with teacher, eventually giving in and pretending that I understood..

http://i80.photobucket.com/albums/j199/pugfug90/CEPE.gif
Umm..
Perhaps I'm having more of a hard time than necessary because I keep thinking magnets when I see this diagram..

Basically, the diagram is representing a "situation" "as is".. When you manipulate the lower case +"q" to go towards +Q, PE increases, but PE decreases.. What? Or when you move +q away from Q-, PE increases but potential energy decreases? Too confused..

2007-02-20 10:18:14 · 2 answers · asked by pugfug90 2

How's this sound?

A beetle sits near the rim of a turntable that is at rest, but is free to rotate about a vertical axis. What happens if the beetle begins to walk around the perimeter of the turntable? Does the beetle move relative to the ground? Consider the limits of a very massive turntable and a very light turntable.

Yes, the beetle moves relative to the ground. Because to every action, there is an equal and opposite reaction (Newton’s Third Law), the table would try to turn in the opposite direction. If it is a very light turntable, we would be able to see some motion, but not for a heavy one.

2007-02-20 10:15:09 · 1 answers · asked by SMS 1

2007-02-20 10:10:00 · 13 answers · asked by NILAY MITASH 1

Your car rolls slowly in a parking lot and bangs into the metal base of a light pole. In terms of safety, is it better for your collision with the light pole to be elastic or inelastic? Explain.

Here is what I have so far, please advise:

On one hand it is better to have an elastic collision, because then the body receives less of a jerk. If the collision is completely inelastic, then all the kinetic energy of the moving car converts into shock energy all at once which gives the body of the driver a more severe jerk.

IYet it could be better if it the collision is inelastic because then the light pole gives your car only enough impulse to bring it to rest. If the collision is elastic, the impulse given to the car is about twice as much. This additional impulse-which acts over a short period of time-could cause more injury.

2007-02-20 09:56:25 · 3 answers · asked by SMS 1

Here is what I have so far, please let me know if I'm on the right track. Thanks!

When the ball hits the floor each successive time, some of the energy gets transferred to the floor as impact and heat energy. Further, some of the energy is expended in moving against air friction. Therefore, each successive time, the ball rises to a lower height because of energy losses.

As the ball falls, gravitational potential energy is converted into kinetic energy. When the ball hits the floor, some of the kinetic energy is converted to sound energy and heat, some to a compression of the ball-like compressing a spring. The ball now rebounds, converting the potential energy of compression back to kinetic energy. Finally, the kinetic energy of the ball is converted back to potential gravitational energy as the ball rises. The final height of the ball is less than its initial height because some energy has left the system in the form of sound and heat.

2007-02-20 09:53:31 · 1 answers · asked by SMS 1

which one of these bridges has been made the first to the last, Arched bridge, suspension bridge , wood bridge, and irod bridge

2007-02-20 08:57:37 · 1 answers · asked by Anonymous

Where can I find a website which gives the definition of "polar second moment of area"

2007-02-20 08:55:19 · 1 answers · asked by Anonymous

What is the most dense matter on earth? I am talking about something that I could hold in my hand, not something created in a particle accelerator that disappears after .0000000000001 seconds.

2007-02-20 08:51:42 · 3 answers · asked by mhunt3 1

if i point a light at one, the light will reflect onto all of them, will the light be continuos if i creat a closed circle?

2007-02-20 08:50:26 · 4 answers · asked by Anonymous

2007-02-20 08:49:07 · 4 answers · asked by Minamoto 1

An ac voltage, whose peak value is 180 V, is across a 365 resistor. What is the value of the rms current in the resistor? What is the peak current in the resistor?

2007-02-20 08:48:20 · 2 answers · asked by Minamoto 1

My sister's in her first year of college. She tried to take biology, but on her 1st day, the teacher explained to the class that if they hadn't already taken chemistry, they would have a rough time in her biology class. My sister dropped the class a week later due to complete confusion. She then attempted chemistry, but also ended up dropping out of it within the 1st week since she never took chemistry or physics in high school; and doesn't even understand what an atom is! Yes, the school system has failed her, what to do now? I found that physics, since it's the basis for understanding the more abstract concepts introduced in chemistry and biology, would be the best starting point for her. But, physics (along with all sciences) requires lots of math. My sister's taking college algebra right now. My question is, what math courses/subjects are recommended to take/learn before taking a college physics course (assuming no prior chemistry or biology courses have been taken)? thanks

2007-02-20 08:47:36 · 4 answers · asked by World Expert 1

An extension cord made of two wires of diameter 0.129 cm (no. 16 copper wire) and of length 2.6 m is connected to an electric heater which draws 17.0 A on a 120 V line. How much power is dissipated in the cord?

2007-02-20 08:46:48 · 4 answers · asked by Minamoto 1

2007-02-20 08:45:29 · 2 answers · asked by Minamoto 1

A 2.77 kg book is lying on a 0.722 m high table. You pick it up and place it on a bookshelf 2.28 m above the floor. How much work does gravity do on the book?

2007-02-20 08:44:19 · 3 answers · asked by N 1

There are three symbols in relativity textbooks that I've never encoutered before and need lots of help with.

1.Einstein summation convetion : Though not really a symbol i still don't quite understand what is meant by it.

2. Upper case lambda with super scripts and subscripts: It seems to be some sort of linear transformation, but I still don't quite understand it.

3. The great demon, the kronecker delta: I really cannot understand what is meant by this.

The reason I have such a hard time with this notation is because I have very little formal education.

However after the symbols are understood, it becomes very lucid.

Can someone please give me a CLEAR and informal description of what this means with examples relating to relativity and tensor analysis?

PS. I don't want some freaking link to wikipedia! Those have no useful information and seem to me like an attempt at increasing the number of questions you answer.

2007-02-20 08:34:15 · 3 answers · asked by Anonymous

You and a friend are glacier climbing. Your friend falls off an icy cliff! Luckily, the two of you are attached by a rope and your friend does not plummet into the abyss. Unluckily, you are attached by a rope and you start sliding off of the cliff! Assuming there is no friction between the rope and the icy cliff, determine the acceleration of you and your friend and the tension T in the rope. The tension and acceleration should be ONLY in terms of your mass (m1), your friend’s mass (m2) and acceleration due to gravity (g). But don’t worry, you have a pick axe and the outlook is not so grim (but the rescuing part is not included in this problem). Draw 2 free body diagrams.

So far I have a= (Fnorm+Fmg+FT(tenstion))/(m1+m2)

And tension, T= (m1m2)/(g(m1+m2))

Is that right or wrong?

2007-02-20 08:13:11 · 1 answers · asked by Anonymous

2007-02-20 08:11:05 · 3 answers · asked by STORMY K 3

An electric car accelerates for 8.0 s by drawing energy from its 325 V battery pack. During this time, 1460 C of charge pass through the battery pack. Find the minimum horsepower rating of the car.

2007-02-20 08:02:00 · 1 answers · asked by madison c 1

An axon is the relatively long tail-like part of a neuron, or nerve cell. The outer surface of the axon membrane (dielectric constant = 5, thickness = 1 10-8m) is charged positively, and the inner portion is charged negatively. Thus, the membrane is a kind of capacitor. Assuming that an axon can be treated like a parallel plate capacitor with a plate area of 5.8 10-6 m2, what is its capacitance?

2007-02-20 08:00:13 · 1 answers · asked by madison c 1

A sailboat race course consists of four legs, defined by the displacement vectors A,B ,C, D and , as the drawing indicates. The magnitudes of the first three vectors are A = 3.10 km, B = 5.50 km, and C = 5.10 km. The finish line of the course coincides with the starting line. Using the data in the drawing, find the distance of the fourth leg and the angle thetha

http://edugen.wiley.com/edugen/courses/crs1507/art/qb/qu/c01/ch01p_47.gif.

2007-02-20 07:55:02 · 1 answers · asked by Alex G 1

2007-02-20 07:32:54 · 4 answers · asked by NILAY MITASH 1

I have noticed that whenever my clock speeds up, I have to replace the batteries and it is counter intuitive. So if someone can explain this.

2007-02-20 07:28:30 · 1 answers · asked by sohil1027 1

If someone could do this, would it be right, even if they had Lucifer cover for them and no one could prove it?

Why would they do this?

2007-02-20 07:08:33 · 3 answers · asked by Phone E 3

Does anyone know how to find an induced magnetic field?

2007-02-20 07:08:26 · 4 answers · asked by Anonymous