Physics - April 2007

I do know something about the ionosphere and how it reflects radio waves, but never really got why it should be the AM frequencies that travel so far.

2007-04-24 04:49:15 · 4 answers · asked by Diana 2

2007-04-24 04:39:28 · 11 answers · asked by Anonymous

Howdy, everyone.

I'm solving a ballistic problem about a bi-dimensional motion of a projectile, thrown from coordinates x=0 and y=0.

Take that I've a degree a = 20° and an initial velocity Vo = 20.0 m/s. I'd solve the problem this way:
first of all, I'd find the x and y components of Vo, that would be VoX (20.0 m/s * cos a) and VoY (20.0 m/s * sin a).
Then onto the half-height time: Ti = Vfy - VoY / Ay (remembering that Vfy in this case is 0.0 m/s since the velocity in the peak of the motion is = 0.0 m/s).
Then I'd multiply this result by 2 to get the full time of the motion and get the total time Tf.
That way I can calculate the range: dx= VoX * tf.
To get the hmax (the peak height) I'd do: hmax= VoY * Ti + 1/2 g * t^2.
I wanted to know if this procedure is correct.

Then, another question. Put that I've the same problem (a = 20° and V0 = 20.0 m/s). But the projectile is thrown from a mountain (for istance) and the height of this cliff is 10 m.

How can I solve it?

2007-04-24 04:36:20 · 2 answers · asked by Anonymous

2007-04-24 04:30:40 · 9 answers · asked by Anonymous

2007-04-24 02:41:16 · 6 answers · asked by Anonymous

2007-04-24 02:32:36 · 1 answers · asked by ggkvarma 2

why is it that one needs more illumination when using high levels of magnification (pertaining to the microscope)

2007-04-24 02:12:09 · 3 answers · asked by bhiboy 1

2007-04-24 02:06:53 · 3 answers · asked by dorai 1

1.The acceleration of a 82 kg couch that is pushed across the floor with an unbalanced force of 21 N?
2. The force needed to accelerate a 1357kg car forward at 8.0 m/s2?
3.The mass in kg of an object that weighs 1225 N on Earth?
4.What unbalanced force is needed to give a 976kg car an acceleration of 2.50 m/s2?
5. A FORCE OF 240.0 N causes an object to accelerate at 3.2 m/s2. What is the mass of the object?
6. A 0.25kg steel ball experiences a net force of 1.15 N as it rolls down a ramp. What is the acceleration of the ball?
7. The velocity of a 90.5kg man running south with a momentum of 389kg. M/s?
8. What is the momentum of a 10.0kg dog chasing a rabbit north at 6.0 m/s?

2007-04-24 00:50:00 · 1 answers · asked by Anonymous

Answers in brackets, How do you get to the answers? tnx

A car goes around a curved stretch of flat roadway of radius R = 114.0 m. The magnitudes of the horizontal and vertical components of force the car exerts on a securely seated passenger are, respectively, X = 205.0 N and Y = 552.0 N.

q.What is the minimum coefficient of static friction between the tyres and the road needed to negotiate this turn without sliding out? (0.371)

This stretch of highway is a notorious hazard during the winter months when it can be quite slippery. Accordingly the LTSA decides to bank it at an angle φ = 24.0 ° to the horizontal.

q. At what speed could the car now negotiate this curve without needing to rely on any frictional force to prevent it slipping upwards or downwards on the banked surface?(80.3)

q. Suppose the above car negotiates the banked curve at 100 km/h maximum safe speed. What are the horizontal and vertical force components this car now exerts on the seated passenger? (383 and 582)

2007-04-23 23:53:32 · 1 answers · asked by Anonymous

According to the classical model of materiality, all matter is made up from an indivisible substance. Therefore our definition of materiality is based on this idea that at root matter is substance, something physical with three dimensions. If this is no longer true, does it mean there is no matter, as understood in the classical sense? I’m no scientist; therefore I would appreciate a simple explanation as to the nature or properties of matter as understood today, related to the classical understanding of matter.

2007-04-23 22:31:38 · 3 answers · asked by Anonymous

I just read in the Economist that nuclear fusion produces much less radioactive waste than nuclear fission. Now, I've always thought that nuclear fusion produces ZERO radioactive waste. Can anyone explain where this comes from?

2007-04-23 21:22:02 · 2 answers · asked by Ricky Bobby 3

How would you prove energy has no volume?

2007-04-23 20:52:42 · 6 answers · asked by Professor Small - check myspace 2

2007-04-23 20:39:38 · 6 answers · asked by david s 1

The coefficient of static friction between Teflon and scrambled eggs is about 0.03. What is the smallest angle from the horizontal that will cause the eggs to slide across the bottom of a Teflon-coated skillet?

2007-04-23 19:41:08 · 1 answers · asked by drobi27 1

Or that the laws of physics temporarily changed to allow for a jet fuel fire to burn at a steadily increasing temp outside of a blast furnace and work its way down instead of up to destroy each floor before the next fell on it to allow it to collaps at freefall speed.

2007-04-23 19:40:31 · 7 answers · asked by Anonymous

while performing the practical for determination of acceleration due to gravity using compound pendulum at first the time period decreases but at end it INCREASES?
WHY THIS HAPPENS ?
I WANT REASON ?

2007-04-23 19:17:43 · 1 answers · asked by ASHISH P 1

A helium-neon laser (wave length=633nm) illuminates a diffraction grating. The distance between the two m=1 bright fringes is 32 cm on a screen 2.0 m behind the grating.

2007-04-23 19:13:31 · 1 answers · asked by RhondaJo 2

2007-04-23 19:06:38 · 1 answers · asked by shell f 1

Consider a person standing on ground and a train moving at a high velocity in front of him. Which of these bodies' time is slowed? Please explain me the reason. Thanks.

2007-04-23 18:49:03 · 4 answers · asked by Harsh 2

Compute the integration of zdv over R ,R is the region above the rectangle whose vertices are (0,0,0), (2,0,0), (2,3,0) , and (0,3,0) and below the plane z=x+2y

2007-04-23 18:47:42 · 1 answers · asked by maake_naki 1

I'm currently stuck on question....

Describe how the following quantities are interrelated on a CRT: accelerating and deflecting voltage and deflection distance.

Thanks ~!

2007-04-23 18:15:21 · 1 answers · asked by Anonymous

Does time move in increments of Planck time? Is there an instantanious jump from one planck time to another? Is this a screwy question?

2007-04-23 17:50:59 · 4 answers · asked by TRAF 4

2007-04-23 17:22:58 · 3 answers · asked by stumped on physics 2

if you have a known amount of electric charge and an appropriate voltmeter how would you measure this capacitance

2007-04-23 17:19:35 · 2 answers · asked by stumped on physics 2

ok well i have to do a project on velocity and momentum so what should i do???

2007-04-23 16:51:52 · 8 answers · asked by Anonymous

2007-04-23 16:40:41 · 3 answers · asked by marinesista84 1

at what distance will the moon gravity be stronger than the earth gravity?
the earth-moon distance is 384403 km

2007-04-23 16:38:20 · 3 answers · asked by wills 3

2007-04-23 16:34:12 · 2 answers · asked by Anonymous

This question inspired by:
On the discovery channel, a frog was levitated in a magnetic field because it contained water, a dipole.

2007-04-23 16:28:39 · 2 answers · asked by Anonymous