Physics - November 2007

1-It falls with constant acceleration.
2-It falls with constant speed.
3-It falls with decreasing acceleration.
4-It falls with decreasing speed.
And why?

2007-11-16 00:38:52 · 7 answers · asked by Anonymous

1. Find the resultant vector (value and angle) when the following two vectors are added together:
R1 = 22.4 m, θ = 26.6 degrees
R2 = 29.2 m, θ = 59 degrees

2. Find the resultant vector (value and angle) when the following two vectors are added together:
R1 = 40.3 m, θ = 7.1 degrees
R2 = 15.0 m, θ = -180 degrees


Answers:
1. |R| =
θ =
2. |R| =
θ =


***She gave us this link but i dont know how to use this thing... i am horrible at physics or anything to do with math related questions....

http://phet-web.colorado.edu/simulations/vectormath/vectorMath.swf

2007-11-15 23:53:07 · 3 answers · asked by Anonymous

2007-11-15 21:39:45 · 5 answers · asked by David C 1

It's for a project due in two hours. I've been working all night. That's six hours straight. At the computer. I can't feel my eyes anymore. And lucky me, I still have more work to do.

2007-11-15 20:09:59 · 7 answers · asked by Anonymous

Basically looking for 3 phase inverter design based on mosfet or IGBT

2007-11-15 18:37:14 · 1 answers · asked by Satendra Pal S 1

In Einstein's equation E= mc^2,

What does m stand for? If it's the mass, then what mass? Could it possibly the mass defect which is the difference between the mass of an atom and the sum of its protons, neutrons, and electrons?

Also, if c is the speed of light, which equals 3.0x10^8 then does c^2 equal (3.0x10^8)^2? or no?

And the E is the energy in joules, right?

Thank you!

2007-11-15 18:10:50 · 10 answers · asked by Diamond 3

A. They are always equal in magnitude to forces acting in the opposite direction.

B.Their magnitudes increase with increasing speed.

C.They always act in the same direction as the object's acceleration.

D.They act in a direction opposite to the object's motion.

E. They always act in a direction opposite to the object's acceleration.

2007-11-15 18:00:28 · 1 answers · asked by Hades Lee 2

2007-11-15 17:22:33 · 4 answers · asked by Anonymous

Is it possible to connect multiple power supplys, say from two or three or 6 smaller generators, to have more power? Like 1,000 little fans on your roof... And if so, do you have a link where there is information about it?

2007-11-15 17:18:30 · 2 answers · asked by ntlgnce 4

A small wooden boat floats in a swimming pool, and you’re observing the water level at the edge of the pool. Consider the following situations, and explain whether the water level will rise, fall, or stay the same:
(a) The boat is removed from the water
(b) The boat was originally holding an iron anchor which is then removed from the boat and placed on the shore.
(c) The boat was originally holding an iron anchor which is then removed from the boat and dropped in the pool.

2007-11-15 16:45:50 · 4 answers · asked by Nik 1

I have a bunch of ideas of what I want to be when I graduate HS. I have potential. I know that. One of them is being a weapons engineer for either the US Military (preferably USMC) or for an armory company (Like Colt or Springfield). But right now, I'm just curious about the flight pattern of... say... a catapult? But I don't want to wait till Junior year to learn physics, and don't want to spend money on a book. Any good sites?

2007-11-15 16:16:34 · 3 answers · asked by Anonymous

2007-11-15 15:31:22 · 6 answers · asked by tam_conato 1

A rod of Pyrex glass is precisely measured against an aluminum measuring stick at a temperature of 20°C, and the length of the rod is measured as exactly 25.0 cm. The temperature in the lab is then raised to 35°C for one hour, and then the Pyrex rod is measured a second time against the same measuring stick. The second measurement of the rod’s length can be expected to be:
A. 25.0 cm.
B. greater than 25.0 cm.
C. less than 25.0 cm.
D. less than or equal to 25.0 cm.

2007-11-15 15:26:41 · 1 answers · asked by Anonymous

A hydroelectric dam holds back a lake of surface area 2.9×106 m^2 that has vertical sides below the water level. The water level in the lake is a height 150 m above the base of the dam. When the water passes through turbines at the base of the dam, its mechanical energy is converted into electrical energy with 90 % efficiency.

What volume of water must pass through the dam to produce an amount of electrical energy totalling 1000 kilowatt-hours of electrical energy?
What distance does the level of water in the lake fall when this much water passes through the dam?

2007-11-15 14:38:30 · 2 answers · asked by Anonymous

This is a rather advanced problem, so either skim it or dig in!

If all space were empty except for two nearby masses, say two drops of water, the drops would, according to Newton's Law of gravity, be attracted together. Now suppose all space were full of water except for two bubbles. How would the bubbles move?

a) They would move apart
b) They would not move at all
c) They would attract each other

2007-11-15 14:26:05 · 6 answers · asked by ? 6

A 69 kg diver jumps off a 10.4 m tower.
(a) Find the diver's velocity when he hits the water.
m/s __________
(b) The diver comes to a stop 2.0 m below the surface. Find the net force exerted by the water.
___________Newtons

2007-11-15 14:25:44 · 1 answers · asked by Anonymous

Two identical containers are open at the top and are connected at the bottom via a tube of negligible volume and a valve that is closed. Both containers are filled initially to the same height of 1 m, one with water, the other with mercury. The valve is then opened. Water and mercury are immiscible. Determine the fluid level in the left container (water) when equilibrium is reestablished.

2007-11-15 14:21:23 · 1 answers · asked by Ariel 2

Two blocks of masses 9kg and 18kg are placed on a horizontal, frictionless surface. A light spring is attached to one of them, and the blocks are pushed together with the spring between them. A cord holding them together is burned, after which the block of mass 18kg moves to the right with a speed of 13 m/s. What is the velocity of the other mass in m/s?

This is how I thought you did it...
(18kg)(0) + (9kg)(0) = (18kg)(13m/s) + (9kg)(Vf)

Vf=26m/s but thats not right :( what am I doing wrong?

2007-11-15 14:12:26 · 1 answers · asked by Katie E 2

2007-11-15 14:10:42 · 4 answers · asked by dands81184 2

A person who weighs 740 N steps onto a spring scale in the bathroom, and the spring compresses by 0.69 cm.
(a) What is the spring constant?

I don't know..I tried k=740/.69, but this was incorrect.

(b) What is the weight of another person who compresses the spring by 0.29 cm?

This one I got. I set .69/.29=740x and got 311N which was correct. I don't know why I can't get the first part, but I would really appreciate anyone who would help me out! :)

2007-11-15 13:59:59 · 5 answers · asked by NoV A 2

2007-11-15 13:59:06 · 1 answers · asked by *click* 3

Two blocks, A and B, are connected by a compressed string. The mass of bock A is twice that of block B. Immediately after release, compare the net force on block A to the net force on block B. The table is frictionless and the mass of the spring is zero.

1)There is no net force on block A or block B.

2)Fnet of A is equal in magnitude and direction to Fnet B and not zero.

3) Fnet B, will be in the opposite direction and half as large as Fnet A.

4)Fnet A, and Fnet A are both directed toward the left with Fnet A larger than Fnet A, but not twice as large. Block A is pulling block B.

5) Fnet A, will be in the opposite direction and half as large as Fnet B.

6) Fnet A is equal in magnitude and opposite in direction to Fnet B, and not zero.


I think it is 5 because A is twice as massive as B so it would take more force to move it the the same and they will be going in opposite directions. Do you agree?

2007-11-15 13:42:41 · 5 answers · asked by Katie E 2

a 900-kg car strikes a huge spring at 20 m/s compressing it 5.0 meters. (a) what is the spring constant of the spring? (b) how long is the car in contact w/ the spring b4 it bounces off in the opposite direction?

2007-11-15 13:35:34 · 1 answers · asked by some guy 2

there are 12 liters of water there are three containers one that holds 12 liters, another that holds 7, and another holding 5.
how do i get 2 6 liters?

2007-11-15 13:32:24 · 1 answers · asked by angie 2

Discuss in detail buoyancy and its relationship with Archimedes principles.

2007-11-15 13:31:23 · 4 answers · asked by juwiegorawr 2

i need to know this before i go to bed cause i have a test and i need to understan this

2007-11-15 13:23:53 · 2 answers · asked by diva 1

As a rocket carrying a space probe accelerates away from Earth, the fuel is being used up and the rocket's mass becomes less. When the mass of a rocket (and its fuel) is M and the distance of the rocket from the Earth's center is 1.5rE, the force of gravitational attraction between Earth and the rocket is F1.

When some fuel is consumed causing the mass to become 0.5M and the distance from Earth's center is 2.5rE, the new gravitational attraction is f2. Determine the ratio of F2 to F1.
The symbol rE is earth's radius.

2007-11-15 13:21:24 · 2 answers · asked by To-the-Stars 4

2007-11-15 13:17:12 · 5 answers · asked by Victoria R 2

it flies at this angle and a wind blows directly east at 520 N, it acts with this force due east every 100 meters the bird rises, so how much work is done on the bird during each 100m of its rise by this force... having trouble setting up my free body diagram to determine correct angle and stuff... help please!!!!

Best answer to first correct response, thanks all

2007-11-15 13:14:47 · 1 answers · asked by Anonymous

Monochromatic light ( wavelength= 593 nm ) is incident normally on the diffraction grating containing 600 lines/mm. Find the angles at which one would observe the first order maximum angle1 and the second order maximum angle2.
If the distance between the diffraction gratings and the screen x = 0.300 m, then find the positions of these diffraction maxima on the screen y1 and y2, respectively.

Any idea how to set this up?

2007-11-15 13:12:57 · 1 answers · asked by Kelly 1