Physics - April 2007

I've been looking everywhere, and I haven't found out a detailed explanation of the effects of temperature on Ohm's law. I know that an increase in temperature means an increase in resistance, and thus a decrease in current, in order for voltage to remain constant. But my teacher says that I need to elaborate a lot more on this. Can someone help me?? Thanks heaps!

2007-04-17 19:20:14 · 5 answers · asked by Anonymous

weight? What is the mechanism?

My teacher posed this question to the classroom, and I can't find the answer. I read about forces, but don't know how the floor "knows." Any help?

2007-04-17 18:55:26 · 3 answers · asked by Anonymous

2007-04-17 18:21:29 · 3 answers · asked by chris 1

short and just with point

2007-04-17 18:19:02 · 1 answers · asked by Yew T 1

3.00*10^-3 kg of gold is deposited on the negative electrode of an electrolytic cell in a period of 2.65 h. Calculate the current in the cell during that period

i think this helps but what goes where?
I=changeQ/change t = ne / change t

2007-04-17 17:18:56 · 1 answers · asked by bippidibopiddi 2

The atmospheric pressure above a swimming pool changes from 755 to 765 mm of mercury. The bottom of the pool is a rectangle (12 m x 24 m). By how much does the force on the bottom of the pool increase?

2007-04-17 17:13:59 · 2 answers · asked by Anonymous

So the bulbs are in parallel. Instead of having one bulb in each of the parallel sides, however, there are two bulbs on each of the sides. The first side closest to the battery has 80 watt and 120 watt bulbs in series, and the second parallel side has 160 watts and 240 watts in series. Rank the brightness of bulbs, explain.

2007-04-17 16:51:38 · 2 answers · asked by Jonathan J 1

A wad of sticky clay with mass m and velocity Vi is fired at a solid cylinder of mass M and radius R. The cylinder is initially at rest and is mounted on a fixed horizontal axle that runs through its center of mass. The line of motion of the projectile is perpendicular to the axle at a distance d < R from the center.

find the angular speed of the system after the clay hits the cylinder

is mechanical energy conserved?

2007-04-17 16:44:09 · 1 answers · asked by Anonymous

You are flying in an ultra-light aircraft at a speed of 34.7 m/s. An eagle, whose speed is 19.7 m/s, is flying directly toward you. Each of the given speeds is relative to the ground. The eagle emits a shrill cry whose frequency is 3610 Hz. The speed of sound is 330 m/s. What frequency do you hear?

2007-04-17 16:35:24 · 1 answers · asked by Psychotic Bunnie 1

2007-04-17 15:59:24 · 6 answers · asked by LITTLE_JOHN 5

ARE THERE THE SAME AMOUNT OF PROTONS AND ELECTRONS IN AN ELEMENT! i don't now how to find electrons!!!

2007-04-17 15:33:49 · 12 answers · asked by Welshy! 1

Let's say that a runner whose mass is 50kg stumbles and falls on her extended arm. If the arm's bones absorb all of the kinetic energy (disregarding the energy of the fall), determine the mininum velocity of the runner in which would make the arm bone break. Lets say the arm is 1m long and that the straight section area of the bone is 4cm^2.

The runner has healthy bones.
Please help out! there must be a way to answer this. thanks!!

2007-04-17 15:33:24 · 2 answers · asked by jamet002 2

describe how you might convert the elastic potential energy of a coiled spring into thermal energy. How might you convert thermal energy into gravitational potential energy?

2007-04-17 15:28:24 · 1 answers · asked by Anonymous

For safty in climbing a mountaineer uses a nylon rope that is 22 m long and 1.5 cm in diameter. when supporting a 94 kg climber, the rope elongates 1.6 m. find youngs modulus ? answer in units of Pa ?

I used the equation:

Y= (F/A)/(delta L / L initial )

and i get .226768 but it seems to be wrong ?

2007-04-17 15:26:24 · 3 answers · asked by Anonymous

2007-04-17 15:12:49 · 3 answers · asked by HZW 1

this has to be the stupidest question but i don't care

2007-04-17 14:43:08 · 4 answers · asked by mhlad2003 2

A cylinder with moment of inertia I about its center of mass, mass m, and radius r has a string wrapped around it which is tied to the ceiling. The cylinder's vertical position as a function of time is y(t).

At time t=0 the cylinder is released from rest at a height h above the ground.

Part A) The string constrains the rotational and translational motion of the cylinder. What is the relationship between the angular rotation rate w and v, the velocity of the center of mass of the cylinder?

Remember that upward motion corresponds to positive linear velocity, and counterclockwise rotation corresponds to positive angular velocity.

1) Express w in terms of vand other given quantities.

2) Suppose that at a certain instant the velocity of the cylinder is v. What is its total kinetic energy, Ktot, at that instant?
Express Ktotal in terms of m,r , I, and v.

3) Find vr , the cylinder's vertical velocity when it hits the ground.

2007-04-17 14:37:04 · 1 answers · asked by ? 1

1.) The intensity of solar radiation varies inversely with the square of the distance from the sun. The earth is an average of 1.5 x 10^8 km from the sun.

How close to the sun should the earth be for the solar radiation pressure to be 1.0 Pa?

2007-04-17 14:04:06 · 1 answers · asked by Tyler D 1

its for my science physics final and i cant come up with anything that works for the past 2 months! the rules are you cant use propellers, fire, water, electricity or air. and it has to be able to stop at a certain distance ....
HELP

2007-04-17 13:48:54 · 2 answers · asked by obsessedw/nowandl8erz&ladybugz 2

A Ball Rolling Uphill. A bowling ball rolls without slipping up a ramp that slopes upward at an angle B to the horizontal. Treat the ball as a uniform, solid sphere, ignoring the finger holes.

1) What is the acceleration of the center of mass of the ball?


2) What minimum coefficient of static friction is needed to prevent slipping?

2007-04-17 13:35:04 · 2 answers · asked by ? 1

the quantization of charge implies that the number of field lines emanating from a point charge is an integer N depending on the charge, is it true?

2007-04-17 13:26:51 · 1 answers · asked by stumped on physics 2

Can RC circuits discharge current in such a way that it could be used as a timer or clock? Id imagine it wouldnt last forever and it would not 'oscillate' like an RL circuit would.

2007-04-17 12:51:30 · 3 answers · asked by leikevy 5

2007-04-17 12:32:44 · 1 answers · asked by Anthony C 1

An aluminum calorimeter with a mass of 105 g contains 240 g of water. The calorimeter and water are in thermal equilibrium at 14.5 degrees C. Two metallic blocks are placed into the water. One is a 56.5-g piece of copper at 67 degrees Celsius. The other block has a mass of 333 g and is originally at a temperature of 124 degrees Celsius. The entire system stabilizes at a final temperature of 25 degrees
Celsius.
Determine the specific heat of the unknown sample. Take the specific heat of water to be 1 cal/kg*degree C.

2007-04-17 12:32:02 · 0 answers · asked by steve 1

a long uniform pole, initially lying horizontal, is pulled up so that it stand vertical. the pole is 7 feet long, ang weight 1000 pounds
what work is required to pull it up?

2007-04-17 12:29:51 · 1 answers · asked by Anonymous

Does anything (object, particle, etc) not contain energy? Some particles are said to be massless so can the opposite be true? Are some particles energyless?

2007-04-17 12:27:33 · 7 answers · asked by Anonymous

Thanks!

2007-04-17 12:11:57 · 6 answers · asked by Jess 1

An electron with initial kinetic energy of 4.0 keV enters Wall 1 at time t = 0.

Wall 1 contains a uniform magnetic field directed towards it with magnitude 0.010 T. The electron goes through a half-circle then exits Wall 1, headed towards Wall 2 across a gap of 25 cm.

There is an electric potential difference V = 2000 V across the gap, with a polarity such that the electron's speed increases uniformly as it traverses the gap.

Wall 2 contains a uniform magnetic field directed against it with magnitude 0.020 T. The electron goes through a half-circle and the leaves Wall 2.

At what time t does it leave?

I am just stuck with where to start! Please point me in the right direction. Give me the answer so I can check my work. Thanks...

2007-04-17 12:08:58 · 1 answers · asked by mstnglover 2

2007-04-17 11:51:34 · 2 answers · asked by Chuqs U 1

date

2007-04-17 11:33:07 · 4 answers · asked by Anonymous