Physics - December 2007

How much energy is required to change a 20 g ice cube from ice at -40°C to steam at 100°C?

2007-12-03 09:47:55 · 2 answers · asked by Anonymous

My dad said that when things spin they pull objects towards it and the bigger the object, the faster it spins, and the more gravity it has. He said if something really small was spinning a lot faster than something really big than it would have more gravity. I'm learning about this in school and I haven't heard anything of the sort, so I'm seriously doubting my dad's theory...


Could someone give me an accurate explanation of what's actually correct?

2007-12-03 09:46:17 · 4 answers · asked by Anonymous

the pipes leading to the showers in your locker room are old and inadequate. while the city water pressure is 700,000 Pa, the pressure in the locker room when one shower is on is 600,000 Pa. Use poiseuille's equation to calculate the approximate pressure if three shower are on.

P.S. is it trick question. the anser is 400,000 Pa . Please help me out

2007-12-03 09:42:27 · 1 answers · asked by goofy 2

1.One 2.5 kg paint bucket is hanging by a massless cord from another 2.5 kg paint bucket, also hanging by a massless cord,


(a) If the buckets are at rest, what is the tension in each cord?
N (lower bucket)
N (upper bucket)
(b) If the two buckets are pulled upward with an acceleration of 1.50 m/s2 by the upper cord, calculate the tension in each cord.
N (lower bucket)
N (upper bucket)

2. A flower pot with a mass of 9.3kg is hanging by two wires that make an angle of 78° from the horizontal.
What is the tension on each wire? Newtons

What angle would the wires have to be at for the tension on each wire to be 93Newtons? wrong check markdegrees

After watering the plant, the angle of the wires changes to 79° and the tension was 47.5N. How much water was added to the plant? kg.

A third rope is added to the flower pot

If the angle that each rope makes with the horizontal remains 78° and the mass is still 9.3kg, what is the tension on each wire? Newtons

2007-12-03 09:36:39 · 1 answers · asked by Shawn Carter 1

Ok people I have this two problems that I have an idea of how to workout but the answers I get differ from what the book says, so I need someone's help, please!!!

A 55 g ice cube at 0°C is heated until 45 g has become water at 100°C and 5 g has become steam at 100°C. How much energy was added to accomplish the transformation?

How much energy is required to heat 40g ice at -10°C to steam at 110 °C?

2007-12-03 08:56:29 · 3 answers · asked by kryptobud2003 2

Given a slab of material that is 1.2 m^2 and 2.4 × 10^-2 m thick
(a) what is the thermal resistance if the material is asbestos? (b) What is the thermal resistance if the material is iron?
(c) What is the thermal resistance if the material is copper?

2007-12-03 08:49:58 · 1 answers · asked by Jerry M 1

A birch tree loses 667 mg of water per minute through transpiration (evaporation of water through stomatal pores). What is the rate of heat lost through transpiration?

2007-12-03 08:48:26 · 1 answers · asked by Bob P 1

Ice at 0.0°C is mixed with 6 × 10^2 mL of water at 23°C. How much ice must melt to lower the water temperature to 0.0°C?

2007-12-03 08:47:50 · 1 answers · asked by Bob P 1

A solid cylinder (radius = 0.150 m, height = 0.120 m) has a mass of 6.50 kg. This cylinder is floating in water. Then oil ( = 725 kg/m3) is poured on top of the water until the situation shown in the drawing results. How much of the height of the cylinder is in the oil?

2007-12-03 08:28:41 · 1 answers · asked by Anonymous

The height of a certain waterfall is 33.3 m. When the water reaches the bottom of the falls, its speed is 25.8 m/s. Neglecting air resistance, what is the speed of the water at the top of the falls?

2007-12-03 08:26:51 · 1 answers · asked by Anonymous

If a robber needed to jump from one window to another, which was 25 m away and 33 m below his own at a 62 degree angle, what would his initial velocity have to be?

Thanks for all the help!

2007-12-03 08:18:47 · 3 answers · asked by chewd.pencils 2

Does T (the distance between ADJACENT peaks) = P (the period- (timebase x divisions in a cycle))?

So wouldn't that make P = P x time base?
I'm soooooooooooooooooooooo confused :(.

2007-12-03 08:05:26 · 2 answers · asked by Muppet 2

initially at rest. The incoming ball is deected at an angle of 30.1deg from its original direction of motion. Calculate the velocity of the initially moving ball after the collision.


1.20E+01 m/s

1.20E+01 cm/s

1.40E+01 m/s

1.40E+02 m/s

2007-12-03 07:46:49 · 1 answers · asked by Anonymous

Why is the current in an incandescent bulb greater immediatley after it is turned on than it is a few moments later?

2007-12-03 07:24:39 · 3 answers · asked by Anonymous

Escape velocity on the surface is 11.2 km/s.

If a hole is drilled to the center of the Earth, then what initial velocity should have the projectile launched from the center of the Earth in order to escape to the infinity?

2007-12-03 07:08:38 · 3 answers · asked by Alexander 6

http://s226.photobucket.com/albums/dd11/jackphotos123/?action=view¤t=EarthGravity.jpg

2007-12-03 06:58:32 · 2 answers · asked by Anonymous

An accident involves a car of mass 2000 kg which approachs a stationary car of mass 970.0 kg. The driver of car A applies his brakes 15.6 meters before he crashes into car B. After the collision, car A slides 15.6 meters while car B slides 27.9 meters. The coefficient of kinetic friction between the locked wheels and the road for both cars is 0.530. How fast was the driver of car A going before he hit the brakes?

2007-12-03 06:38:55 · 1 answers · asked by Butterfly 67 1

2007-12-03 06:30:44 · 10 answers · asked by Alexander 6

2007-12-03 06:05:41 · 11 answers · asked by autistic24 2

2007-12-03 06:04:58 · 5 answers · asked by Anonymous

Ty in advance x

2007-12-03 06:03:19 · 18 answers · asked by Anonymous

i know that when the water evaporates from your skin which draws heat away from ur body, making u feel cold
but y does it draws heat away from ur body?

2007-12-03 05:44:39 · 10 answers · asked by froggy 2

This is a physics question.

2007-12-03 05:10:33 · 2 answers · asked by Frst Grade Rocks! Ω 7

When you kick a soccer ball (football) with the inside of your right foot, it curves from right to left. The same is true of a volley ball and tennis ball.

But when you do the same thing to a beach ball, it curves from left to right (opposite direction).

Can anyone explain why?

2007-12-03 05:04:21 · 6 answers · asked by Dr D 7

On March 19 the asteroid deviated from Polaris only slightly, while its visible size increased considerably. The astronomers announced that doomsday arrived.

Fortuantely astronomers were wrong. On March 20 the asteroid missed the Earth by mere 100 km.

Two days later astronomers said that right now they could not track the asteroid, because it was passing the bright disk of Sun, and was invisible.

What was velocity of the astroid with respect to the center of Earth at the closest approach?

2007-12-03 04:56:11 · 3 answers · asked by Alexander 6

What is the net force accelerating a 5.0 kg cannonball from rest to 150m/s [W], if the applied force acts for 0.05s?

2007-12-03 04:39:57 · 2 answers · asked by myname_isalbert 1

you know cuz i think religion and morals set boundaries

2007-12-03 04:31:02 · 6 answers · asked by Anonymous

2007-12-03 04:04:21 · 2 answers · asked by cH@r1l3y 2

Can I put something on the parabolic dish to fill the holes to make it becomes more efficient in reflecting waves?

Another question is, can I modify it by adding extra plate around the circle edge of the dish to make it larger to get more waves?

2007-12-03 03:55:34 · 2 answers · asked by Pat 1

A Styrofoam box has a surface area of 0.76 m2 and a wall thickness of 2.0 cm. The temperature of the inner surface is 5.0°C, and the outside temperature is 24°C. If it takes 7.9 h for 5.0 kg of ice to melt in the container, determine the thermal conductivity of the Styrofoam.

2007-12-03 03:19:21 · 2 answers · asked by El Cartel 1