Physics - November 2006

I am stuck on this problem and would be really greatful with any help on it. Thanks a bunch!

A carousel rotates at the rate of 0.15 rev/s with an 80-kg man standing at a point 2.0 m from the axis of rotation.

(a) What is the new angular speed when the man walks to a point 0.7 m from the center? Assume that the carousel is a solid 25-kg cylinder of radius 2.0 m. Answer is in rad/s

(b) Calculate the change in kinetic energy due to this movement. Answer is in Joules

2006-11-15 14:58:50 · 2 answers · asked by Anonymous

what is the magnitude of the air resistance (force) acting on the feather ? How long does it take the feather to drop 10.0m?

2006-11-15 14:55:17 · 2 answers · asked by jennifer n 1

what is the magnitude of the water resistance acting on the anchor ? How fast is the anchor traveling after 3.0 seconds? an How long does it take the anchor to drop 30m?

2006-11-15 14:51:44 · 3 answers · asked by jennifer n 1

Why is it a theory isn't it proven?

2006-11-15 14:48:17 · 11 answers · asked by Anonymous

2006-11-15 14:43:58 · 2 answers · asked by goring 6

An ordinary light bulb consumes 40 W of power. Through what height could a 1000-N object be lifted expending the same amount of power for 6 hours?

a. 860 m
b. 360 m
c. 720 m
d. 650 m

2006-11-15 14:36:46 · 2 answers · asked by Banana28 1

How large a force is required to accelerate a 1600 kg car from rest to a speed of 25 m/s in a distance of 200 m?

a. 1600 N
b. 0 N
c. 200 N
d. 2500 N

2006-11-15 14:30:15 · 2 answers · asked by SMS 1

If you were in a lift and the cables broke at the 5th floor and you managed to 'jump' inside the lift (elevator) a nano-second before it hit the bottom would you survive with no injuries because you were mid-aire for that nano-second while the base of the lift (elevator) hit the ground? It's a question that's bugged me for all time, serious answers only please.

2006-11-15 14:24:19 · 13 answers · asked by Anonymous

I have no idea how to do this problem. Please help me! I will give out 10 points for the best answer.

A stainless-steell orthodontic wire is applied to a tooth (as in the figure I linked). The wire has an unstretched length of 2.8 cm and a diameter of 0.25 mm. If the wire is stretched 0.08 mm, find the magnitude of the force on the tooth. Disregard the width of the tooth and assume that Young's modulus for stainless steel is 18 x 10 to the 10th power Pa.

http://www.webassign.net/sf5/p9_66.gif

2006-11-15 14:12:07 · 2 answers · asked by Seiya 1

2006-11-15 14:06:04 · 2 answers · asked by goring 6

2006-11-15 14:00:19 · 5 answers · asked by goring 6

2006-11-15 13:31:57 · 9 answers · asked by kp000000 1

2006-11-15 13:29:24 · 3 answers · asked by Willem V 3

If anyone can help me out with this I would really appreciate it. I can not come up with the right answer that's in the book.

A student siits on a rotating stool holding two 4.0 kg objects. When his arms are extended horizontally, the objects are 1.0 m from the axis of rotation, and he rotates with an angular speed of 0.75 rad/s. The moment of inertia of the student plus stool is 3.0 kg x m2 and is assumed to be constant. The student then pulls the objects horizontally to 0.30 m from the rotation axis.

1. Find the new angular speed of the student. ____ rad/s

2. Find the kinetic energy of the student before and after the objects are pulled in. ____ J before and ____ J after

2006-11-15 12:52:54 · 2 answers · asked by Michelle 1

If a moving clock appears to be ticking one half as fast as normal, at what percentage of light is it traveling?....

2006-11-15 12:40:54 · 2 answers · asked by El 1 1

thanx..



Terminal Velocity: The constant velocity at which a falling object travels when the size of the upward force of air resistance matches the size of the downward force of gravity.

2006-11-15 12:11:16 · 6 answers · asked by Anonymous

a spherical brass shell has an interior volume of 1.60 x 10^-3 m^3. Within this interior volume is a solid steel ball that has a volume of 0.70 x 10^-3 m^3. The space between the steel ball and the inner surface of the brass shell is filled completely with mercury. A small hole is drilled through the brass, and the temperature of the arrangement is increased by 12 degrees celsius. What is the volume of the mercury that spills out of the hole?

B(brass) = 57 x 10^-6 (degrees celsius)^-1
B(mercury) = 182 x 10^-6 (degrees celsius)^-1
B(steel) = 36 x 10^-6 (degrees celsius)^-1

My Approach:

Change in Velocity = mercury(BVchangeT) - steel(BVchangeT) - brass(BVchangeT)

= (1.6 x 10^-3 - 0.7 x 10^-3)m^3 (182 x 10^-6 celsius^-1)(12 celsius) + (36 x 10^-6 celsius^-1) (0.7 x 10 m^3)(12 celsius) - (1.60 x 10^-3 m^3)( 57 x 10^-6 celsius^-1)(12 celsius)

= 1.17 x 10^ -6 m^3 <----my answer, what do you think?

2006-11-15 12:09:18 · 1 answers · asked by Anonymous

Which is more accurate, to mass the liquid in the small container before pouring it into the graduated cylinder, or to determine its volume first?

2006-11-15 11:57:18 · 2 answers · asked by Nerdybones 2

I need to write an essay and need ideas. The topic I picked is “Conservation of Mechanical Energy"

Here is a quote from the overview that was given to me:

In this physics course you learned a great many scientific concepts: Newton’s three laws, Snell’s law, Archimedes’ principal, conservation of mechanical energy, heat, temperature, gravity, kinetic theory, wave theory of sound and light, to name just a few. Many of these concepts were an entirely different way of understanding and explaining observations. For example, the heliocentric view of the solar system replaced the Ptolemaic view of the solar system.
In this project you will select a science concept that you learned in this class and explain the previous erroneous concept that the new concept replaced. If this was a course in astronomy, for example, you would explain the Ptolemaic system.

Does anybody have any suggestions on what I can write about for "Conservation of Mechanical Energy"

2006-11-15 11:44:55 · 3 answers · asked by Anonymous

1.At room temp., an oxygen molecule, with mass of 5.31 x 10^-26 kg, typically has a KE of about 6.21 x 10^-21 J. How fast is it moving?

2.An 80 g arrow is fired from a bow whose string exerts an average force of 95 N on the arrow over a distance of 80 cm. What's the speed of the arrow as it leaves the bow?

3.If the speed of a car is increased by 50%, by what factor will its minimum braking distance be increased, assuming all else is the same? Ignore the driver's reaction time.

4.A softball having a mass of .25 kg is pitched at 100 km/h. By the time it reaches the plate, it may have slowed by 10%. Neglecting gravity, estimate the average force of air resistance during a pitch, if the distance between the plate and pitcher is about 15 m.

5.A 220 kg load is lifted 21.0 m vertically with an acceleration a = 0.150 g by a single cable. Determine (a) tension in the cable, (b) the net work done on the load, (c) the work done by the cable on the load.

Please show work.

2006-11-15 11:39:27 · 1 answers · asked by hdwong58 3

THE SUM OF A NEGATIVE INTEGER AND A POSITIVE INTEGER IS ZERO

TRUE OR FALSE/ WHAT IT THE ANSWEAR

2006-11-15 11:26:29 · 6 answers · asked by angle2980 2

I would appreciate any helpful input on this physics problem. I am really confused on this one. Thanks for any help :)

A high-speed lifting mechanism suppports a 815 kg object with a steel cable 28.0 m long and 4.00 cm2 in cross-sectional area.

a) Determine the elongation of the cable (in mm).

b) By what additional amount does the cable increase in length if the object is accelerated upward at a rate of 2.7 m/s2 (in mm)?

c) What is the greatest mass that can be accelerated upward at 2.7 m/s2 if the stress in the cable is not to exceed the elastic limit of the cable, 2.2 x 10 to the 8th power Pa (in kg)?

2006-11-15 11:22:38 · 1 answers · asked by Anonymous

A multiple of eleven I be,
Not odd, but even, you see.
My digits are a pair
And when multiplied beware,
Make a square and a
Cube out of me.
What number am I?

2006-11-15 10:58:52 · 3 answers · asked by HOLA 2

What happens if two photons crash, can they?

2006-11-15 10:57:04 · 4 answers · asked by Arkane Steelblade 4

Honey or vegetable oil? I believe honey. In which liquid do you think the particles are more loosely connected?

2006-11-15 10:56:02 · 3 answers · asked by Anonymous

I am stuck on this problem and would be really greatful with any help on it. Thanks a bunch!

A carousel rotates at the rate of 0.15 rev/s with an 80-kg man standing at a point 2.0 m from the axis of rotation.

(a) What is the new angular speed when the man walks to a point 0.7 m from the center? Assume that the carousel is a solid 25-kg cylinder of radius 2.0 m. Answer is in rad/s

(b) Calculate the change in kinetic energy due to this movement. Answer is in Joules

2006-11-15 10:44:31 · 2 answers · asked by Anonymous

...at a point 0.26 m from the center of the bar and sticks to it. At what angular speed does the bar/clay system rotate about its center of mass after the impact?

2006-11-15 10:44:30 · 1 answers · asked by Anonymous

Two spaceships with unlimited acceleration at 1 g leave space dock, the 2nd exactly 1 second after the first. They both accelerate in the same direction. What is the maximum distance the two ships will be separated by.

2006-11-15 10:42:05 · 3 answers · asked by Cirric 7

2006-11-15 10:39:58 · 5 answers · asked by juicy 1

2006-11-15 10:17:32 · 12 answers · asked by juicy 1