Physics - December 2007

How can an electric field have a direction in space although the electric potential has no direction?

2007-12-19 14:39:18 · 3 answers · asked by romaine_style 1

2007-12-19 14:38:12 · 4 answers · asked by jeremy 2

A stone is dropped into a deep canyon and is heard to strike the bottom 10.2 seconds after release. The speed of sound waves in air at the canyon is 334 m/s. How deep is the canyon?

Method and answer would be much appreciated!

2007-12-19 14:30:16 · 3 answers · asked by =) 3

need help with these problems, my physics teacher is evil and when people asks for help he says its physics your not supposed to get it. Please show work so i know how and explain to people

1. In tackling a running back from the other team, a defensive lineman exerts a force of 500N at 180*, while a linebacker simultaneously applies a force of 650N at 270*. What is the resultant force on the carrier?

1. 1 force of 60N and a 2nd of 30N act on an object at point P. Add the vectors and find the magnitude of the resultant at 30*,45*,&60*

2007-12-19 13:48:15 · 1 answers · asked by deathgod197 3

to take my semester exam tomorrow over these kind of problems.


A rock is projected from the edge of the top of
a building with an initial velocity of 23:8 m=s
at an angle of 30± above the horizontal. The
rock strikes the ground a horizontal distance
of 96 m from the base of the building.
The acceleration of gravity is 9:8 m=s2 :
Assume: The ground is level and that the
side of the building is vertical. Neglect air
friction.
What is the horizontal component of the
rock's velocity when it strikes the ground?
Answer in units of m=s.

2007-12-19 12:50:58 · 1 answers · asked by americasnextopfashiondesigner 2

A 2.46 ?F ideal capacitor and a 300 ? resistor are connected in series with an AC source of 120 V (rms) and 60Hz. Find the average power delivered to the circuit. Answer: 3.45 W

Pave= Iv cos () 120 cos() v=IZ Z=Square(r^2+ (wl-xc)^2)

I think this is what you do but i can not get the right answer

2007-12-19 12:46:56 · 1 answers · asked by mastersource2005 5

2007-12-19 12:44:35 · 11 answers · asked by Angelina F 1

confused

2007-12-19 12:20:38 · 2 answers · asked by Anonymous

Question: a cannon sends a projectile towards a target a distance 1350m away. The initial velocity makes an angle of 27 degrees with the horizontal. The target is hit.
The acceleration of gravity is 9.8m/s^2. What is the magnitude of the initial velocity?


I've attmpted this problem like 50 times, but I really don't see how I can get the initial velocity without being given one of the components or something...any ideas?

2007-12-19 12:13:50 · 2 answers · asked by Jackie 1

2007-12-19 11:56:17 · 4 answers · asked by Rima 1

heeeeelpppppp

2007-12-19 11:51:07 · 1 answers · asked by alexpurrsaid 1

An adult exerts a horizontal force on a swing to raise a child a height h above the lowest point of the cycle.

a)What is the horizontal force that the adult exerts?
b) What is the speed of the child at the bottom of the cycle?
c) What is the tension in the rope (use m,L,g)
d) If the child jumps straight off (horizontally) at the bottom of the cycle where will the child land(Assume L = 2m, h= .5 meters and the height above the ground at the lowest point is .5 meters).

2007-12-19 11:48:37 · 1 answers · asked by Ree H 1

2007-12-19 11:34:05 · 5 answers · asked by Humvee256 2

A student drops a ball from a window 3.5 m above the sidewalk. The ball accelerates at 9.80 m/s squared. How fast is it moving when it hits the sidewalk?

I have no idea even how to start this problem, and if you figure it out could you please tell me how you got it and what type of formula you used. Thanks!

2007-12-19 11:07:40 · 4 answers · asked by UMP Skills 3

How many miles is that?

2007-12-19 10:59:56 · 3 answers · asked by honeybear 5

2007-12-19 10:46:14 · 5 answers · asked by Alexander 6

What is the ratio of the periods of two identical pendulums oscillating on a planet X and on the Earth? (The acceleration of free fall on the planet X is 1.62 m/s2)

I have no idea...

2007-12-19 10:10:42 · 2 answers · asked by jabba 3

I have no idea of how projectiles work and i need lots help in my physics class thank you very much if you can help me.

Symmetric
object launched at 60 degrees Vx=120m/s whatis the Vi?
How high does it go and what is the impact velocity.

Asymmetric
Mortar 250meters above a target, target 750meters horizontally away.If shells burts 6meter above ground If the Vi=225m/s what is the launch angle?

How do you find the range and max height with only the Vi, launch angel, Sine, Cosine, Vx, and Vi,y?

It would be very helpful if you can show the steps. Thank you very much!

2007-12-19 10:06:36 · 1 answers · asked by Serena M 1

1/ A heat engine operating between temperatures of 500K and 200K is used to lift a 10-kg mass vertically at a constant speed of 5m/s.
(a) Determine the power the engine must supply ro lift the mass (hint: mechanical power).
(b) Determine the maximum possible efficiency at which the engine can operate.
(c) If the engine were to operate at the maximum possible efficiency, determine the following...
i) The rate at which the hot reservoir supplies heat to the engine
ii) The rate at which heat is exhausted to the cold resevoir.

2007-12-19 10:03:33 · 1 answers · asked by leonardo 1

A 20 kg mass, released from rest, slides 6 meters down a frictionless plane inclined at an angle of 30 degrees with the horizontal and strikes a spring of spring constant k =200 newtons/meter as shown in the diagram above. Assume that the spring is ideal, that the mass of the soring is negligible, and the mechanical energy is conserved.
a) Determine the speed of the block just before it hits the spring.
b) Determine the distance the spring has been compressed when the block comes to rest?
c) Is the speed of the block a maximum at the instant the block strikes the spring?
d) if there is friction and a coefficient of .2 what is the speed of the block just prior to hitting the spring?
e) Imagine that there is no friction in the region where the spring is. What would be the distance that the block would travel up the incline after it rebounded from the spring?

2007-12-19 10:03:02 · 1 answers · asked by Ree H 1

2007-12-19 09:45:50 · 4 answers · asked by loops 1

Does anyone know how to derive expressions in terms of m, G, M, and x for the kinetic energy of a satellite and for the gravitational potential energy of a satellite?

2007-12-19 09:37:25 · 2 answers · asked by asianman 4

2007-12-19 09:31:07 · 6 answers · asked by loops 1

capacitance is directly proportional to area and inversely to distance, so what is capacitance when the plates are brought together?

2007-12-19 09:26:50 · 2 answers · asked by suji 2

my reference table is showing 150. x 10^-8.

Thank you for the help.

2007-12-19 09:22:04 · 1 answers · asked by nidibaby 1

You are explaining to friends why astronauts feel weightless orbiting in the space shuttle, and they respond that they thought gravity was just a lot weaker up there. Convince them and yourself that it isn't so by calculating how much weaker gravity is at h = 490 km above the Earth's surface.

2007-12-19 09:17:36 · 3 answers · asked by hahahahahaha 1

current through the 18 ohms, c) and the effective resistance.

2. solutions for a, b, and c with a parrallel connection.

2007-12-19 09:17:21 · 2 answers · asked by nidibaby 1

(the nut will not break), something to do with forces...

2007-12-19 08:51:34 · 4 answers · asked by Anonymous

Okay the problem says:

A roller coaster cart originally at rest is moved from point A to point B on a chain by a force F, against gravity. It stops temporarily at B. Is the force F conservative or non-conservative? What forms of energy does the cart have at A and B?

I'm confused because I know gravity's a conservative force, but what about friction with the chain? Anyway if anyone can help me out that'd be great, thanks

2007-12-19 08:47:04 · 2 answers · asked by rst41 2

A child tries to drink water through a 1m straw but finds that the water rises only 75cm. By how much has the kid reduced the pressure in her mouth below the atmospheric pressure?

Can someone explain how I do this question?

2007-12-19 08:46:02 · 1 answers · asked by Tomasz K 2