Physics - November 2007

And assuming no friction, what is the acceleration?

2007-11-05 09:46:46 · 2 answers · asked by Anonymous

2007-11-05 09:35:36 · 1 answers · asked by Thomas K 1

An empty rubber balloon has a mass of 0.0120 kg. The balloon is filled with helium at a density of 0.181 kg/m3. At this density the balloon is spherical with a radius of 0.300 m. If the filled balloon is fastened to a vertical line, what is the tension in the line?

2007-11-05 09:30:02 · 1 answers · asked by Anonymous

2007-11-05 09:12:33 · 2 answers · asked by erin k 1

. The traffic light is timed for 15 seconds. If the car’s driver wishes to pass the light without stopping just as turns green again, what will be the speed of the car just it passes the light?

2007-11-05 09:06:49 · 1 answers · asked by navya 1

Say you have a rubber ball with air interior.
Both the rubber ball and the air exhibit spring-like behaviour.
Using Hooke's equation for the rubber (i.e. k = F/x) and the Air Spring Equation for the air ( k = γ.P.s / L), could you compare the stiffness (k) between one another and say which one contributes more to the spring effect that the ball exhibits per unit volume?

2007-11-05 07:27:39 · 5 answers · asked by saman-a-man 1

A 1270 N uniform beam is attached to a vertical wall at one end and is supported by a cable at the other end. A W = 1860 N crate hangs from the far end of the beam

(a) Calculate the magnitude of the tension in the wire. Newtons

(b) Calculate the magnitude of the horizontal and vertical components of the force that the wall exerts on the left end of the beam

Fx = N
Fy = N

http://img107.imageshack.us/img107/9378/p966altcu2.gif

2007-11-05 07:26:19 · 1 answers · asked by Anonymous

In the early morning hours of June 14, 2002, the Earth had a remarkably close encounter with an asteroid the size of a small city. The previously unknown asteroid, now designated 2002 MN, remained undetected until three days after it had passed the Earth. Suppose that at its closest approach, the asteroid was 78300 miles from the center of the Earth -- about a third of the distance to the Moon.

(a) Find the speed of the asteroid at closest approach, assuming its speed at infinite distance to be zero and considering only its interaction with the Earth.

(b) Observations indicate the asteroid to have a diameter of about 2.0 km. Estimate the kinetic energy of the asteroid at closest approach, assuming it has an average density of 3.33 g/cm3. (For comparison, a 1-megaton nuclear weapon releases about 5.6

2007-11-05 07:21:50 · 2 answers · asked by Anonymous

2007-11-05 06:50:42 · 4 answers · asked by baynhamr 1

How much force would she have to exert if the barbell were lifted underwater?

2007-11-05 06:39:47 · 3 answers · asked by Anonymous

Is it possible that :- A constant force is acting on the body but it is still at rest...........

(no Friction, No Inertia)

2007-11-05 05:11:41 · 9 answers · asked by Anonymous

Light of wavelength 659.4 nm is emitted by a star. The wavelength of this light as measured on Earth is 661.1 nm. How fast is the star moving with respect to Earth?

Is it moving toward Earth or away from it?

2007-11-05 04:57:06 · 5 answers · asked by Kelly 1

I don't really get what ohm's law is. And how do we know if one is ohmic conductor or non-ohmic conductor? Why is light globes non-ohmic conductor?

2007-11-05 04:03:58 · 5 answers · asked by Anonymous

These are the questions that I was wondering if you could help me out on:
)Ex1)Derive formula for linear accelerated motion:
xfinal = (xintial) + (vinitial)t + 1/2at^2
2)Derive formula for circular motion:
a=v^2/r
3)Show that energy conservation is independent of the shape of the surface.
Consider an incline and prove for arbitrary shape. Consider conserved forces.

Any insight you could offer me would be greatly appreciated.
Thanks!

2007-11-05 03:52:45 · 1 answers · asked by Amber G 2

http://i242.photobucket.com/albums/ff276/carolineboy/physics2.jpg

I got:

1B,2B,3A,4A,5D,6C,7D,8D

2007-11-05 03:50:45 · 2 answers · asked by Joe T 1

Is there some kind of math symbol? Or would greater than/less than be appropriate?

2007-11-05 03:33:16 · 3 answers · asked by monicanena 5

how can a small force produce a large change in momentum ?

2007-11-05 03:22:20 · 2 answers · asked by Anonymous

2007-11-05 03:15:52 · 5 answers · asked by poppinoffalot 2

Just checking to see if I've made any mistakes in my hw problems...
1. A block of mass m is at rest on an inclined plane as shown in the figure. Find an expression for the static friction in terms of the mass , the acceleration of gravity, and and the angle shown.
1. The attempt at a solution:
http://www.physicsforums.com/attachm...3&d=1194247920
Newtons 1st Law
sum of forces = 0
mg cos(a) -μs * mg sin (a) = 0
μs = cos(a)/sin(a) = cot(a)
thus: static frictoin = cot(a)*cos(a)
2. A proud new BMW owner drivers her car at a speed of 25 m/s into a corner. The coefficients of friction between the road and the tires are 0.70 (static) and 0.40(kinetic). What is the minimum radius of curvature for the corner in order for the car not to skid?
2. Speed(v) of honda = 25 m/s
Coefficient of kinetic friction(μk) = 0.40

2007-11-05 03:08:02 · 4 answers · asked by korr 2

2007-11-05 02:43:45 · 2 answers · asked by Anonymous

1) Why in math do we replace the cross product between radius and Force to
calculate Torque, with the sine function? Why can't we use cosine instead?

2007-11-05 01:32:57 · 1 answers · asked by Anonymous

Who knows a general penetration formula for projectiles?

2007-11-05 01:29:42 · 1 answers · asked by Anonymous

2007-11-05 00:28:17 · 8 answers · asked by Anonymous

In the following question, the answer is a
http://tinyurl.com/2musg7

My understanding is,
amount of work done of conservative force
=amount of decrease of potential energy
=amount of increase in kinetic energy

decreases of word done of nonconservative force
=decreases of mechanical energy of the entire system

Am I correct?

2007-11-04 23:39:39 · 1 answers · asked by Anonymous

The answer is c, but I can't figure out what is the reason, can somebody kindly explain it?
http://tinyurl.com/32322t

2007-11-04 23:38:41 · 2 answers · asked by Anonymous

Can someone please give the meaning of strain??

2007-11-04 23:30:00 · 2 answers · asked by ryahdiaz 3

2007-11-04 23:12:57 · 13 answers · asked by Kirsty l 1

Third Law of thermodynamics (ABSOLUTE ZERO)
Why is it that as the minimum temperature is approached, the further extraction of energy becomes more and more difficult?

2007-11-04 22:34:26 · 2 answers · asked by beachball_boink 1

can anyone explain this to me?

2007-11-04 22:30:21 · 1 answers · asked by oopsy 1

Can any one explain me what "Red Shift" is in Astronomy?

2007-11-04 22:24:01 · 5 answers · asked by 3.14 2