Physics - November 2007

A car weighing 1451 kg. is traveling at 48.0 km/hr.

How much kinetic energy does it possess?

I need the answer in Joules.

2007-11-28 05:50:25 · 4 answers · asked by nickj3315 2

How to make a dc motor?
Question Details: I want to know how can I make a dc motor, with only a battery, magnets, paper clips, cooper wires, leads, etc.

Thanks

2007-11-28 05:34:17 · 1 answers · asked by km1988 1

Calculate the electric power produced per square meter of windmill operating at 70 % of the theoretical maximum efficiency, with an electric generating efficiency of 90% when the wind velocity is 10 m/sec.

2007-11-28 04:36:45 · 1 answers · asked by Anonymous

If the wind blows for one year at a steady 10 m/sec, how much would be the energy we could get in this year per square meter of cross section through the use of a windmill? Express the answer in kWh. (use air density of 1kg/m3)

2007-11-28 04:34:33 · 1 answers · asked by Anonymous

Help! I am 14 years old and I am doing a science project At What Velocity Does My Punch Have To Travel To Stop A Human Heart? I video recorded my punches and uploaded the video showing the duration of my punch from frames 50:19 to 50:23 -so .4secs. 50:21-50:23=.2sec. Using the formula F=ma 2.27kgsx.4m/s/s=.908newtons and 2.27kgsx2.2m/s/s=.54newtons. The 2.27kgs I turned pounds into kgs I looked up on the internet . My fist is about 5lbs. Please check if this is correct. If it is I would like to graph it. What graph should I use bar, linear. . Thamk you .

2007-11-28 03:46:55 · 2 answers · asked by Alfred R 1

2007-11-28 03:26:30 · 4 answers · asked by Anonymous

IThis was posted before, here's the slightly corrected version).

At 12:00 noon, Twin A with clock stays at rest while Twin B with telescope jumps to 4/5ths speed of light. Twin B, using telescope, observes Twin A's clock going more slowly because of relativistic doppler. After some time, Twin B suddenly reverses course and heads home at 4/5ths speed of light. Still using the telescope, Twin B observes Twin A's clock going faster, again because of relativistic doppler. At 1:00 pm, he notices that Twin A's clock now also shows 1:00 pm. When Twin B arrives back home with Twin A, how much older is Twin A than Twin B?

Bonus question: Why does Twin A, using telescope, never sees Twin B's clock showing the same time as Twin A's clock?

2007-11-28 02:23:20 · 4 answers · asked by Scythian1950 7

I've heard it said for years that according to the laws of thermodynamics, a bumblebee should not be able to fly. Has scientific knowledge increased enough to explain the discrepancy?

2007-11-28 01:44:56 · 4 answers · asked by night_train_to_memphis 6

hocker players hits ball of mass 0.2kg. The contact time between the stick and the ball is 0.3s and the force exerted on the ball by the stick is 60N. Find the speed in which the ball leaves the stick.

This simple one baffled me for some reason =(

2007-11-28 01:39:44 · 3 answers · asked by Anonymous

Two weeks ago a monkey faced the daunting task of retrieving a bottle of Vodka that Lewis Carroll had stashed on his roof. The monkey beat the challenge and shared the Vodka with his good friend the Cheshire Cat. See http://answers.yahoo.com/question/index;_ylt=AhvKefOetlVmVzowiKt64NLsy6IX;_ylv=3?qid=20071114125308AAbeCwb

But now, Carroll has a new bottle and he has also rigged the mechanism so the Monkey can't use his old trick.

A Cable hangs over frictionless pulley, next to roof on which is nice bottle of Vodka. The cable has uniform mass.

A weight hangs on one end of the cable, on the other side, the monkey has a knot he can sit on. The weight and the monkey balance exactly.

Additionally to prevent the monkey from climbing up the cable until the weight jams into the pulley, Carroll attached a latch. If the weight gets too high up the latch is triggered, the weight falls to the ground as so does the monkey.

Within minutes, the monkey had stolen the vodka.

2007-11-28 01:30:05 · 2 answers · asked by Frst Grade Rocks! Ω 7

Good day to all science inclined people!

In Cebu City, Philippines, the MATH MAJOR'S CIRCLE made a contest named Science Olympiad wherein it gathers students from the province and city of Cebu.

I participated this contest just 8 hrs ago with two members in my team in University of San Carlos - North Campus. We placed 4th among sixteen schools in Cebu.

For me, as a SENIOR high school student, I'm very happy because my golly...other schools like Science High and etc. are hard to beat especially the fields tackled are GENERAL SCIENCE, BIOLOGY, CHEMISTRY, PHYSICS, GEOLOGY and ASTRONOMY.

What do you think?

2007-11-28 01:24:41 · 3 answers · asked by Anonymous

and moves to the left at a speed of 3m/s if the second cart has mass of 3 kilograms it will move to the right speed of/?

2007-11-28 00:56:37 · 2 answers · asked by Anonymous

A weight is attached to a hanging end of a string, which on the other side is attached to a cart on a track. Why does the heavier weight pull the cart faster if all objects fall at the same rate?

2007-11-28 00:05:45 · 6 answers · asked by CJSlove 2

2007-11-28 00:05:41 · 3 answers · asked by bob m 3

2007-11-27 21:39:23 · 14 answers · asked by matthew b 4

If your frame of reference was a photon, would the speed of a different photon still be constant?

2007-11-27 19:37:51 · 8 answers · asked by John K 3

2007-11-27 18:23:27 · 3 answers · asked by Kirin Desuke 2

2007-11-27 17:57:27 · 12 answers · asked by Anonymous

A wire with mass 100g is stretched so that its ends are tied down at points 92.0cm apart. The wire vibrates in its fundamental mode with frequency 70.0 Hz and with an amplitude of 0.500cm at the antinodes.

What is the speed of propagation of transverse waves in the wire?

What is the tension in the wire?

2007-11-27 17:36:38 · 2 answers · asked by KT 1

A barge filled high with sand approaches a low bridge over the river and cannot quite pass under it. Should sand be added to, or removed from, the barge? (13-10)

please help, thanks!

2007-11-27 16:40:45 · 3 answers · asked by Callie 1

13-5, please help, thank you!

2007-11-27 16:39:08 · 3 answers · asked by Callie 1

An object with weight 50 N is attached to free end of a light string wrapped around a reel of radius 0.25 m and mass 3 kg. The reel is a solid disk, free to rotate in a vertical plane about the horizontal axis passing through its center. The hanging object is released 6 m above floor. Part of the ques. asks me to determine tension in the string, so I drew a free-body diagram, but how can I determine tension with no acceleration?

2007-11-27 16:30:35 · 3 answers · asked by Muffins 1

The oxygen molecule, O2, has a total mass of 5.30 10-26 kg and a rotational inertia of 1.94 10-46 kg·m2 about an axis through the center of the line joining the atoms and perpendicular to that line. Suppose the center of mass of an O2 molecule in a gas has a translational speed of 580 m/s and the molecule has a rotational kinetic energy that is 2/3 of the translational kinetic energy of its center of mass. What then is the molecule's angular speed in rad/s about the center of mass. Thanks a lot for your help!

2007-11-27 15:40:47 · 1 answers · asked by locowise 2

2007-11-27 15:39:45 · 3 answers · asked by Redfalcongt 2

how do you solve it? and what is the final answer?

2007-11-27 15:38:08 · 4 answers · asked by joe s 1

Our local public radio station (KJZZ) broadcasts at a frequency of 91.5 MHz.

A. What is the wavelength of the radio waves emitted by the KJZZ broadcast antenna? (m)

B. What is the wavelength of the radio waves emitted by the antenna of an AM station broadcasting at a frequency of 1545 kHz? (m)

2007-11-27 15:34:27 · 4 answers · asked by ariddlegirl 1

Why are circuit diagram used rather than drawings of the actual parts of a circuit?
What are the two main parts of an electric current?

2007-11-27 15:30:27 · 2 answers · asked by Anonymous

A person cranks an electric generator to simultaneously power 5 electric light bulbs. Each 5.4 V bulb is drawing 0.28 A of current. Ignoring all resistance in the rest of the circuit, what is the power output of the person? (W)

2007-11-27 15:30:24 · 1 answers · asked by ariddlegirl 1

In a room, you notice that there are two lights that "buzz" at two different pitches that you hear makes an interval of a minor third. You play middle C on the (in-tune) piano in the room, and hear that it makes an interval of a major tenth with the lowest "light buzz".

a) What are the frequencies of the buzzes? (Assume Pythagorean tuning.)
b) What are the notes of the buzzes?
c) What is the quality of the chord that these three pitches make?
d) What note would you need to make it into a minor seventh chord and what is the frequency of that note? (The root does not have to stay the same)

2007-11-27 15:25:23 · 2 answers · asked by Anonymous

A 109kg crate is pulled along a level surface by an engine. The coefficient of kinetic friction between the crate and the surface is 0.28. The acceleration for gravity is 9.8m/s^2 how much power must the engine deliver to move the crate at a constant speed of 4.04m/s. answer in units of watts. also, how much work is done by the engine in 3.64 minutes.

I have no idea how to do this....

2007-11-27 14:44:47 · 1 answers · asked by Katie E 2