Physics - September 2007

CHOICES:
a. The energy of the movig objects before and after impact is the same time
b. The total momentum in an isolated system is constant
c. The mass of the objects before and after collision remains the same
d. the velocity of the objects before and after collision is the same.

If you have an answer please state the reason.
Thanks!

2007-09-04 23:42:32 · 4 answers · asked by Anonymous

At a junction of three wires, two of the wires have currents of +3A and -6A (+ means towards the junction). The third has an 8A fuse in it. Is the fuse likely to burn out?

I think u have to use Kirchoff's Law here, about all currents adding up to 0, but how does that answer the question?
Please explain?

2007-09-04 23:37:03 · 3 answers · asked by Anonymous

If not, what kind of radio waves can pass through walls?

2007-09-04 22:36:53 · 2 answers · asked by junior 1

2007-09-04 22:25:25 · 7 answers · asked by Rex R 1

there will be no current without a potentiol difference,is there an existence of a current source?

2007-09-04 22:05:55 · 3 answers · asked by Anonymous

Applying Bernoulli's theorem to the steam nozzle,

(p1/density*g)+((v1^2)/(2*g))+z1=(p2/density*g)+((v2^2)/(2*g))+z2........(1)

do we get,

(p1/density*g)-(p2/density*g)=((v2^2)/(2*g))-((v1^2)/(2*g))........(a)

since,
by can celling z1 and z2,

Is z1 always equal to z2 for steam nozzle?

There is another equation similar to the above mentioned equation 1 ie...,
(h1)+((v1^2)/2)+z1*g+Q=(h2)+((v2^2)/2)+z2*g+W.............(2)

In what cases do we apply equation (2)?

plz explain the terms in equation (2).

When to apply equation (2) for steam nozzle?and when to apply equation (1) for steam nozzle?

If equation (a) is true then can we say nozzle converts pressure drop into gain in kinetic energy?

It is said that nozzle converts heat energy into kinetic energy?can u plz explain how is it possible?

These questions keeps on haunting my mind!!
My heartily request is to please answer all or at least few of these questions.
Thanking you!!!!

2007-09-04 21:07:55 · 3 answers · asked by C P 1

Help please!

Two charges are located along the x axis: q1 = +6.0 µC at x1= +4.0 cm, and q2 = +6.0 µC at x2 = -4.0 cm. Two other charges are located on the y axis: q3 = +3.0 µC at y3 = +5.0 cm, and q4 = -8.0 µC at y4 = 7.0 cm. Find the net electric field magnitude and direction) at the origin.

2007-09-04 20:09:01 · 3 answers · asked by GSU 1

Why are we supposed to start viewing something using LPO before HPO? Does it affect the image if you use HPO before LPO?

2007-09-04 20:09:01 · 3 answers · asked by topsyturveey 1

The question: There are 3 substances, that is solid, liquid, and gas substance. Between those three substances, there is one substance named plasm. Tell anything you know about plasm.

Experts Only! Serious answers needed!

2007-09-04 19:18:13 · 4 answers · asked by q is stupid 3

I've tried to work them out and answer them.
I don't seem to get the correct answers. Please help.

1) During a hard sneeze, your eyes might shut for 0.42 s. If you are driving a car at 78 km/h during such a sneeze, how far does the car move during that time?

2) In 1 km races, runner 1 on track 1 (with time 2 min, 39.18 s) appears to be faster than runner 2 on track 2 (2 min, 39.25 s). However, length L2 of track 2 might be slightly greater than length L1 of track 1. How large can L2 - L1 be for us to conclude that runner 1 is faster?

3) A particle's position is given by x = 18.0 - 15.0000000000000000t + 3t2, in which x is in meters and t is in seconds. Where is the particle when it momentarily stops?

4) At a certain time a particle had a speed of 14 m/s in the positive x direction, and 6.8 s later its speed was 85 m/s in the opposite direction. What was the average acceleration of the particle during this 6.8 s interval?

2007-09-04 19:17:16 · 2 answers · asked by Timmmsays 2

i am writing up a lab for my physics class and i do not know the law of physics...can u guys help me out?? thanks if u can

2007-09-04 18:32:42 · 6 answers · asked by youngjess90 2

HELP!!!

2007-09-04 18:30:24 · 3 answers · asked by That guy 1

Awnser fast!! I dont know how to do it :(

2007-09-04 18:27:06 · 2 answers · asked by That guy 1

Is is true that alpha and beta rays are more dangerous when swallowed or inhaled because of their ionizing powers?
Then how about gamma rays which have powerful penetrating capabilities?

2007-09-04 17:38:30 · 3 answers · asked by Anonymous

When a 100-N bag of nails hangs motionless from a single vertical strand of rope, how many newtons of tension are exerted in the strand?

How about if the bag is supported by four vertical strands?

2007-09-04 17:16:46 · 2 answers · asked by Anonymous

2007-09-04 17:13:41 · 2 answers · asked by Anonymous

Show how to figure it out please?

2007-09-04 16:39:24 · 1 answers · asked by jumba 1

Two blocks, each of mass M, are connected by at extensionless string of length L. One block is placed on a smooth horizontal surface, and the other block hangs over the side, the string passing over a frictionelss (massless) pulley.

a. Find the Lagrangian

b. Determine y(t) (assume y(t=0)=0 and y'(t=0)=0)

2007-09-04 16:38:06 · 2 answers · asked by Stephanie 1

A subway train starts from rest at a station and accelerates at a rate of 1.60 m/s2 for 14.0s. It runs at constant speed for 70.0s and slows down at a rate of 3.50 m/s2 until it stops at the next station. Find the total distance covered. Could someone please help me set this up and solve it. I believe the answer is around 1.8km. Thanks

2007-09-04 16:10:02 · 2 answers · asked by dantheman772 2

what is the minimum speed to leap off the cliff to miss the ledge at the bottom that is 1.75 m wide and 9.00 m below the cliff?

v= m/s

2007-09-04 16:08:22 · 1 answers · asked by thewayworldturns 2

2007-09-04 16:00:13 · 4 answers · asked by shecries4you 1

2007-09-04 15:52:31 · 5 answers · asked by lolabarry 2

A ball is kicked from a location < 6, 0, -7 > (on the ground) with initial velocity < -9, 19, -4 > m/s. The ball's speed is low enough that air resistance is negligible.

What is the velocity of the ball 0.4 seconds after being kicked? (Use the Momentum Principle!)

I've got the x and z velocity's they are simple.

I would like an example of how to work this out, but if you feel giving me an answer is cheating I'll happily take info on how to use the momentum principal.

2007-09-04 15:22:30 · 2 answers · asked by Anonymous

2007-09-04 15:10:51 · 12 answers · asked by john r 1

A spaceship travelled at a uniform velocity of 3.2 x 10^4 km/h for 2.7 days. What was the displacement of the spaceship?

2007-09-04 14:44:44 · 1 answers · asked by Anonymous

Thank you

2007-09-04 14:42:15 · 5 answers · asked by jumba 1

and what height did it reach?

2007-09-04 14:39:52 · 3 answers · asked by Anonymous

2007-09-04 14:37:32 · 8 answers · asked by hp 1

PAPERS?!?!?!?! i printed out these format papers for my homework and i guess i left them on the counter in the kitchen. anyways, i need them now and i cant find them and so i ask my mom and she says she put them on my desk so i go and look for them and LO AND BEHOLD, they are NOT THERE. i am completely miffed not only becuase my mother always smooshes my things but IF THEY WERE THERE WHY ARENT THEY THERE NOW?!?!?!?!!?!?!?!?!?!?!?!? I looked underneath my desk, bed, chair, everything. where are they please tell me.

2007-09-04 14:33:55 · 6 answers · asked by Michelle 4

i need to find a formula to find time, when a ball is roled down a ramp at various heights and lengths, i need to find the time it would take for that ball to reach the bottom of the ramp. So i guess the givens are height (or angle) of the ramp, length of the ramp, and i know the weight of the ball. I just need a formula to find the time it would take, given those variables if that makes any sense?

2007-09-04 13:47:57 · 1 answers · asked by Anonymous