Physics - November 2007

A mass of 8.60 kg rests on a smooth surface inclined 37.0(deg) above the horizontal. It is kept from sliding down the plane by a spring attached to the wall. the spring is aligned with the plane and has a spring constant of 125 N/m. How much does the spring stretch?

2007-11-02 02:19:02 · 3 answers · asked by Anonymous

I mean Alpha are He nucleus (Atomic mass=4)
Why are not emitted simplier particles, like for example H nucleus (Atomic mass=1) emitted?

2007-11-02 01:50:40 · 1 answers · asked by Anonymous

2007-11-02 01:46:40 · 1 answers · asked by Anonymous

Of course, I know the weight per atom is higher, but it also should be higher the atom size.
Why it is not proporcional?

2007-11-02 01:07:21 · 5 answers · asked by Anonymous

2007-11-02 00:30:27 · 5 answers · asked by spencer 2

We don't get the same attraction when we take our palm towards our stomach, forehead or otherside of the palm.

2007-11-01 23:48:48 · 10 answers · asked by Gan 1

A man with mass 70.0 kg stands on a platform with mass 25.0 kg. He pulls on the free end of a rope that runs over a pulley on the ceiling and has its other end fastened to the platform. The mass of the rope and the mass of the pulley can be neglected, and the pulley is frictionless. The rope is vertical on either side of the pulley.

Question: What is the acceleration of the rope relative to him?

the platform has an upward acceleration of 1.8 m/s
And I have found the force he needs to pull is 551N

2007-11-01 20:28:29 · 2 answers · asked by Potato Monster 2

Find the initial velocity of the rocket shooting up at 150 feet. (Assuming it went up straight) Find the time it takes to go up.

THis is my last problem and i am stuck please help!

2007-11-01 20:19:49 · 5 answers · asked by Michael 2

overtake kart XJ,however kart XJ then accelerates at a constant of 0.25mph each second until it passes ZX. How long will ZX be ahead XJ?

Been having trouble solving this one,please show in as detailed as possible. Thankx for the help everyone.

2007-11-01 19:24:28 · 3 answers · asked by Luv Dual-Core 2

2007-11-01 17:35:43 · 4 answers · asked by meeme821 1

The forces acting on a 2.8kg mass are F1=F1xi-F1yj and F2=F2xi+F2yj where F1x=3N, F1y=8N, and F2x=6N, and F2y=2N and I have to find the magnitude a of the acceleration of the particle. We were told to use a=F1x+F2x/m i + -F1y+F2y/m j, then a=axi+ayj so what I did was 3+6/2.8 + -8+2/2.8 but I got the answer wrong if you know could you help me out please.
There was an example and it was that a 2kg mass is acted on by four forces F1 is 10 N due E, F2 is 8 N due N, F3 is 16 N due S, and F4 is 1 N due W. And the answer for the magnitude of the acceleration was 6.02 but I don't get how they got it so I don't get the other question.

2007-11-01 17:35:17 · 1 answers · asked by glance 3

A woman with mass 50.0 kg is standing on the rim of a large disk that is rotating at 0.500 rad/s about an axis perpendicular to it through its center. The disk has a mass of 110 kg and a radius of 4.00 m.

Calculate the magnitude of the total angular momentum of the woman-plus-disk system, assuming that you can treat the woman as a point.

2007-11-01 17:29:39 · 1 answers · asked by ! 2

An electroscope is a simple device consisting of a metal ball that is attached by a conductor to two thin leaves of metal foil protected from air disturbances in a jar. When the ball is touched by a charged body, the leaves of foil that normally hang straight down spread apart. WHY???

2007-11-01 17:29:15 · 1 answers · asked by Anonymous

2007-11-01 17:28:15 · 4 answers · asked by hlc25895 1

I cannot figure out this problem, I figured out the answers for part (a) and (d) but I cannot figure out parts (b) and (c). I have tried every equation and plugged and chugged and still no correct answer...Help! Please!

A rotating star collapses under the influence of gravitational forces to form a pulsar. The radius of the star after collapse is 3.00 10-4 times the radius before collapse. There is no change in mass. In both cases the mass of the star is uniformly distributed in a spherical shape.

(a) What is the ratio of the angular momentum of the star after collapse to before collapse?

The answer to part (a) is 1

(b) What is the ratio of the angular velocity of the star after collapse to before collapse?

(c) What is the ratio of the rotational kinetic energy of the star after collapse to before collapse?

(d) If the period of the star's rotation before collapse is 2.00 107 s, what is its period after collapse?

The answer to (d) is 1.8 seconds

2007-11-01 17:03:16 · 3 answers · asked by Anonymous

=D You are so smart

2007-11-01 16:58:34 · 2 answers · asked by jennaczar 1

A hammer slides down a roof that makes a 32degree angle with the horizontal. What are the magnitudes of the components of the hammer's velocity at the edge of the roof if it is moving at a speed of 6.25 m/s

please help me understand how to do this problem please! i will choose a best answer

2007-11-01 16:56:08 · 3 answers · asked by Anonymous

Because there is no air or atmosphere, what would it do?


and why?

2007-11-01 16:36:38 · 3 answers · asked by Anonymous

i really dont understand the gas laws. like temperature, pressure, and gas? and how if one changes, it affects another. one example is if a balloon is in the atmosphere on a cold day, the temperature has decreased, so does the pressure and volume decrease too? or does it increase. i would really appreciate if you could explain, because i have a test tomorrow, and ive been studying these gas laws for the past hour, and im more confused. PLZ HELP!!!

2007-11-01 16:18:47 · 5 answers · asked by ~hersh101~ 2

Sorry to ask such a question, but our study group is at a loss as how to continue and our homework is due tomorrow. So here goes:

In order to receive credit we MUST use calculus techniques:

We have a piece of wire that is 100cm long and we're going to cut it into two pieces. One piece will be bent into a square and the other will be bent into a circle. Determine where the wire should be cut so that the enclosed areas will be at maximum. Note that it is possible to have the whole piece of wire go either to the square or to the circle

2007-11-01 16:11:56 · 3 answers · asked by pyrojelli 2

We have this lab setup with an airtrack and two carts of different masses. They each have a magnet on them so they repel each other. This is for a high school physics class and we want them to weigh the carts and let them start with zero initial speed. Then they will let them go and we have meters that measure their speeds. So they could do this once and figure out if the two carts end with the same momentum but how can they do a bunch of trials and end up with a %uncertainty? The two momentums should be the same, but for each trial, they might be different. How can they calculate a result that says, yes, momentum is conserved?

2007-11-01 15:28:14 · 1 answers · asked by califrniateach 4

Until he was in his seventies, Henri LaMothe excited audiences by belly-flopping 9 m into 30 cm of water. Assuming that he stops just as he reaches the bottom of the water, find the magnitudes of the average force and the total impulse on him from the water. Assume his mass is 60 kg.

I calculated the total impulse to be 783.5 N*s. What would the average force be? I know it's impulse/change in time but I am having trouble calculating it. Thanks for your help!

2007-11-01 15:26:24 · 1 answers · asked by locowise 2

A hollow spherical shell is rolling without slipping or sliding down a board that is tilted at an angle of 34.0° with respect to the horizontal. What is its acceleration?

2007-11-01 15:14:52 · 1 answers · asked by Anonymous

A 2.5 -kg block slides down a 25 degree inclined plane with constant acceleration. The block starts from rest at the top. At the bottom, its velocity reaches .65 m/s the lenght of the incline is 1.6m.

what is the coefficent of friction between the plane and the book?

2007-11-01 14:56:38 · 1 answers · asked by james 2

Can anyone tell me what Baryonic matter is and Baryonic dark matter is

2007-11-01 14:48:15 · 1 answers · asked by tjakk 1

The diffraction pattern from a single slit is viewed on a screen. Using blue light, the width of the central maximum is 2 cm

(b) If the blue light has wavelength 0.39 m and the red light has wavelength 0.8 m, what is the width of the central maximum when red light is used?

2007-11-01 14:47:32 · 1 answers · asked by Anonymous

The central bright fringe in a single slit diffraction pattern from light of wavelength 516 nm is 2.3 cm wide on a screen that is 1.05 m from the slit.

(a) How wide is the slit?

(b) How wide are the first two bright fringes on either side of the central bright fringe? (Define the width of a bright fringe as the linear distance from minimum to minimum.)

2007-11-01 14:46:22 · 1 answers · asked by Anonymous

The drawing shows a collision between two pucks on an air-hockey table. Puck A has a mass of 0.022 kg and is moving along the x axis with a velocity of +5.5 m/s. It makes a collision with puck B, which has a mass of 0.062 kg and is initially at rest. The collision is not head-on. After the collision, the two pucks fly apart with Puck A angle 65 degrees and Puck B 37 degrees.

Find the final speeds of both puck A and puck B?

2007-11-01 14:40:34 · 2 answers · asked by bigg310ez 1

The drawing shows a collision between two pucks on an air-hockey table. Puck A has a mass of 0.022 kg and is moving along the x axis with a velocity of +5.5 m/s. It makes a collision with puck B, which has a mass of 0.062 kg and is initially at rest. The collision is not head-on. After the collision, the two pucks fly apart with the angles shown in the drawing.

2007-11-01 14:22:02 · 2 answers · asked by bigg310ez 1

Im doing a rport and need to no who created table salt

2007-11-01 14:04:09 · 4 answers · asked by Broken_Hearted_Angel! 1