Physics - September 2007

We live on a lump of rock travelling through space at 60,000 miles an hour, tied to a giant ball of fire with an invisble string. How can we expect anything to be logical?

2007-09-26 09:39:48 · 20 answers · asked by Uchimataman 1

ablock of mass 25 kg slides down a frictionless surface inclined at 30 degree. to ensure that the block does not accelerate, what is the smallest force that you must exert on it and what its direction??

Please help me with this and i will really appreciate it.

2007-09-26 09:39:24 · 2 answers · asked by hahahaha 2

Since time is not an absolute, without motion or physical body can time travel only exist in human thoughts?

2007-09-26 09:32:56 · 2 answers · asked by edubya 5

can u please explaine how u get ther answer

2007-09-26 09:31:02 · 2 answers · asked by Doubledog 1

2007-09-26 08:46:11 · 4 answers · asked by Anonymous

im building a bottle rocket for science, is there a good way to figure out how long my string should be for my parachute?

2007-09-26 08:41:32 · 1 answers · asked by Anonymous

2007-09-26 07:49:00 · 2 answers · asked by Anonymous

Neglecting air resistance, if you throw a baseball at 20 m/s to your friend who is on the first base, will the catching speed be greater than, euals to or less than 20m/s? Does the speed change if air resistance is factor?

2007-09-26 07:42:54 · 2 answers · asked by Anonymous

2007-09-26 07:02:58 · 6 answers · asked by Anonymous

conduction
convection
evapouration
radiation

2007-09-26 07:01:55 · 2 answers · asked by olliemagik 2

The goose has a mass of 24.4lbs and is flying at 9.00 (miles per hour). What is the kinetic energy of the goose?

2007-09-26 06:17:50 · 2 answers · asked by stranger 1

A small drop of water is suspended motionless in air by a uniform electric field that is directed upward and has a magnitude of 8420 N/C. The mass of the water drop is 3.10 10-9 kg.
(a) Is the excess charge on the water drop positive or negative?
(o) positive
(_) negative

Why?

(b) How many excess electrons or protons reside on the drop?

2007-09-26 06:05:21 · 1 answers · asked by Matt A 1

a room of 70 deg fer., 50 pounds mass of air, and 10 pounds of mass of water vapor.. how do i calculate the energy needed to cool the air down to 55 deg. fer. .. plz i need help.. what equation do i use

2007-09-26 05:53:58 · 2 answers · asked by masrbobo 1

2007-09-26 05:50:23 · 5 answers · asked by madnsane 2

Here's the problem....

A speed skater moving across frictionless ice at 8.40 m/s hits a 4.80-m-wide patch of rough ice. She slows steadily, then continues on at 5.70 m/s.

What is her acceleration on the rough ice?


I dont want the answer, I just want to know how to solve it. Its been bugging me that I cant find the solution to this problem. I have tried different methods and none of the answers I got were correct.

2007-09-26 05:49:18 · 3 answers · asked by Anonymous

I am doing a lab report on wave propogation, and the lab manual and the textbook both say that "a spherical wave has a spreading factor of 1/r", however everything I know about physics tells me that it should be 1/r^2. The lab question asks "what is the spreading factor for a 1-D wave? 2-D? 3-D?", which I would think would be 1, 1/r, and 1/r^2 respectively. Am I missing something here or is the book wrong?

2007-09-26 05:47:20 · 1 answers · asked by MooseBoys 6

Two forces F_1 and F_2, act at a point. F_1 has a magnitude of 9.00 and is directed at an angle of 63.0 degrees above the negative x axis in the second quadrant. F_2 has a magnitude of 5.20 and is directed at an angle of 53.7 degrees below the negative x axis in the third quadrant.

2007-09-26 05:47:18 · 1 answers · asked by bg 1

How far below an initial straight-line path will a projectile fall in one second? Is this depend on the angle of launch or on the initial speed of the projectile?

2007-09-26 05:45:46 · 3 answers · asked by Summer W 1

a) Calculate the braking time

b) Calculate the deceleration of the aircraft

AS Physics questions, thanks.

2007-09-26 05:44:44 · 3 answers · asked by Anonymous

a) Calculate its acceleration

b) Calculate the distance it moves in this time.

AS Physics homework, I'm really stuck, thanks.

2007-09-26 05:42:22 · 4 answers · asked by Anonymous

The voltage output of an AC source is given by the expression:-
deltaV=(200V)Sin wt. Find the r.m.s. current in the circuit when the source is connected to a 100ohm resistor.

2007-09-26 05:24:33 · 3 answers · asked by Anonymous

A soccer ball of diameter 31cm rolls without slipping st a linear speed of 2.3m/s. Through how many revolutions has the soccer ball turned as it moves a linear distance of 15m?

2007-09-26 05:12:48 · 2 answers · asked by Anonymous

Suppose a Chinook salmon needs to jump a waterfall that is 1.50 m high. If the fish starts from a distance 1.20 m from the base of the ledge over which the waterfall flows, find the x- and y-components of the initial velocity the salmon would need to just reach the ledge at the top of its trajectory.
v0x = ________m/s
v0y = ________m/s

Can the fish make this jump? (Assume that a Chinook salmon can jump out of the water with a speed of 6.26 m/s.)
yes or no?

2007-09-26 05:02:27 · 1 answers · asked by wmartine 1

A rocket is launched at an angle of 58.0° above the horizontal with an initial speed of 97 m/s. The rocket moves for 3.00 s along its initial line of motion with an acceleration of 28.0 m/s2. At this time, its engines fail and the rocket proceeds to move as a projectile.
(a) Find the maximum altitude reached by the rocket.
m
(b) Find its total time of flight.
s
(c) Find its horizontal range.
m

2007-09-26 04:59:54 · 2 answers · asked by wmartine 1

can that electricity be stored & used for domestic and industrial purposes???

it's for the science project fair to be held in city..........

i need help.....................please be serious..................

2007-09-26 04:55:05 · 10 answers · asked by smarty 1

please help :( x

2007-09-26 04:54:29 · 4 answers · asked by Anonymous

2007-09-26 04:30:29 · 2 answers · asked by wadood s 1

A hole is drilled through the center of Earth and very long L=100km sealed cylindrical pipe is inserted vertically into the hole. The pipe contains thermally insulated nitrogen gas, which is in equilibrium, has temperature T=400K, and pressure 1atm at the bottom.

Under these conditions the gas can be considered ideal, and pressure of the gas at the top of the pipe is negligible.
Its specific heat Cv = 5/2 R.

The pipe is initially at the sea level, and then is very slowly (adiabatically) lowered downward the center of the earth. As gravity decreases, the gas is able to expand and reach higher levels inside the pipe.

What is temperature of the gas when the pipe is half-way down to the center of the earth?
[in assumption of uniformly dense planet gravity at this point is g/2]

2007-09-26 04:25:30 · 3 answers · asked by Alexander 6

I know it has something to do with the amount of water they displace and bouyance but can anyone give me a better idea as to why it is they float?

2007-09-26 04:25:02 · 4 answers · asked by rubenff2000 1

2007-09-26 04:08:56 · 4 answers · asked by Richie57 1