Physics - July 2006

2006-07-07 01:29:42 · 11 answers · asked by Anonymous

give a good answer.

2006-07-07 00:32:57 · 3 answers · asked by illias k 2

2006-07-07 00:25:31 · 9 answers · asked by farhanhubble 1

2006-07-06 23:14:39 · 5 answers · asked by marvin_jimenez9 1

2006-07-06 23:12:56 · 6 answers · asked by Dipankar D 1

2006-07-06 22:36:40 · 15 answers · asked by tobyfield2003 1

really, though the molecules in space are sparse the darkness in between can't be void of nothingness. But darkness is not energy yet it is infinity and scientific equipment goes off the chart when trying to measure the energy. Strange that no one has been able to harness this energy. Also, a lightbulb in threory forms a vacuum in which there is infinity energy that could, when extracted as dark energy could wipe out earth. I need some real help from anyone from a physics or Astronomy background,

2006-07-06 21:46:37 · 3 answers · asked by Jeanue Voltaire 2

If you fell through (an imaginary tunnel) from one pole to the other or from one side to the other,

how would your weight profile be as you fall from the surface towards the center of the earth?

The weight of an object increases or decreases from the center of gravity. The effect of gravity is inversely proportional to the distance from the centre. so if you were to fall to the center of the earth, how much would you weigh? the radius of the earth at the center is zero so the force on you is infinite??? will you be crushed by gravity?? any clarifications?

2006-07-06 21:34:11 · 14 answers · asked by isahaya 2

one day everything started to get inverted, and what I considered solid suddenly changed - is it possible that I have somehow woken up in a parallel universe? If not, why not?

2006-07-06 21:06:01 · 6 answers · asked by Clark Kenty 1

1. How much energy is needed to melt 3 kg of aluminum at its melting point?
a. 133000 J
b. 1197000 J
c. 262941000 J
d. 399000 J
Questions 2-4
At a steel mill a 50 kg chunk of iron at 22°C is heated to its melting point, completely melted, and then heated more to a final temperature of 1800°C.
2. How much energy is required to heat the iron to its melting point?
a. 35.3 MJ
b. 21.9 GJ
c. 34.8 MJ
d. 40.9 MJ
3. How much energy is required to melt the iron once it reaches its melting point?
a. 14.5 MJ
b. 316 MJ
c. 17.3 GJ
d. 5.78 kJ
4. How much energy is needed to heat the iron the rest of the way to 1800°C after it melts? Assume the same specific heat.
a. 40.9 MJ
b. 34.8 MJ
c. 3.83 GJ
d. 6.1 MJ
5. Why will the sauce of a pizza burn your mouth long after the crust is safe to touch?
a. The sauce has a lower specific heat than the crust.
b. The sauce has a greater specific heat than the crust.
c. The crust does not transfer its heat to you as easily as the sauce does.
d. The sauce is buried too far under other things to get rid of its heat.
6. When water freezes, what happens to the temperature of the surrounding air?
a. The air gets colder because of its proximity to the ice.
b. The air gets warmer because the forming ice gives heat up.
c. The air gets colder because it gives some of its heat to help the water freeze.
d. There is no effect on the temperature of the air.
7. When water vapor (steam) condenses what happens to the temperature of the surrounding air?
a. The air gets warmer because of its proximity to the condensing steam.
b. The air gets warmer because the condensing water gives heat up.
c. The air gets colder because it gives some of its heat to help the water condense.
d. There is no effect on the temperature of the air.
8. Why does warm air rise?
a. It is natural for warm air to rise; this helps keep a steady supply of cooler air near the Earth.
b .Warmer air is less dense than colder air and naturally floats to the top.
c. Warm air is generated by combustion, which uses oxygen. The deficiency of oxygen makes the warm air lighter, so it rises.
d. Warm air radiates its heat away; since heat rises, the air travels with it.
9. What is the amount of energy released by 15 g of tin as it freezes (solidifies) at 232°C?
a. 209 MJ
b. 209 kJ
c. 900 kJ
d. 900 J
10. How much energy is required to melt 85 kg of solid mercury at -39°C?
a. 935 kJ
b.-36.5 MJ
c. 25.1 MJ
d. -464 kJ
11. Sound is transmitted through solids, liquids and gases as the vibration is passed from a molecule to its neighbors. Which of the heat transfer methods is this most similar to?
a. radiation
b. conduction
c. convection
12. Many cooking pots have hard plastic or wooden handles. What is the reason for this?
a. The handles are made from a good conductor of heat so that the heat is drawn away from the pan to protect your hands.
b. The handles are made from a poor conductor of heat so that the heat cannot be drawn into your hands as easily.
c. The handles are made from different materials to make use of the differing chemical properties to block the transfer of heat.
d. When the handles heat up, they expand more than the pot thus allowing the handles to radiate heat away more effectively.
13. What does it mean to say that a material has a high specific heat?
a. It means the material is a poor conductor of heat.
b. It means the material is a good conductor of electricity.
c. It means the material can get very hot compared to other materials.
d. It means the material readily absorbs and releases energy.
14. How can the specific heat be characterized for a material that heats up quickly?
a. It has a low specific heat.
b. It has a high specific heat.
c. It is impossible to make this judgment.
15. What mass of ethyl alcohol will give up 33,000 J of energy as it cools from 27°C to -3°C?
a. 2.41x109kg
b. 0.566kg
c. 1.92×109kg
d. 0.453kg
Questions 16-19
A 75 g chunk of metal is heated to 100°C and then dropped into 0.5 kg of water initially at 22°C. After a short time, the water reaches a final temperature of 23.1°C.
16. How much heat energy does the metal transfer to the water?
a. 345 kJ
b. 345 J
c. 2302 J
d. 24.5 kJ
17. What is the final temperature of the chunk of metal?
a. 23.1°C
b. 22°C
c. 92.7°C
d. 54.9°C
18. What is the specific heat of the metal?
a. 399
b. 27,900
c. 130
d. 377
19. The chunk is most likely made of which type of metal?
a. brass
b. lead
c. tin
d. copper
20. In the old days, it was common to bring a hot object into bed with you on a cold winter night. Which would be better: a 10 kg hot water bottle or a 10 kg iron block, both at the same temperature?
a. The water bottle because water has a higher specific heat.
b. The water bottle because iron has a higher specific heat.
c. The iron block because water has a higher specific heat.
d. The iron block because iron has a higher specific heat.

2006-07-06 20:13:56 · 16 answers · asked by Anonymous

Questions 1-4
The two objects in the diagram below collide.

1. When the objects collide, how do the impulses delivered to each one compare?
a. The first object experiences the greater impulse.
b. The second object experiences the greater impulse.
c. Both objects experience the same impulse.
d. There is not enough information given to determine the greater impulse.
2. When the objects collide, which will experience the greater force from the collision?
a. The first object experiences the greater force.
b. The second object experiences the greater force.
c. Both objects experience the same force.
d. There is not enough information given to determine the greater force.
3. The units of impulse are often expressed as N • s. Which of the following units is equivalent to this?
a. kg m/s2
b. kg m/s
c. kg m2/s2
d. kg m2/s
4. Which object will experience the greater acceleration?
a. The first object experiences the greater acceleration.
b. The second object experiences the greater acceleration.
c. Both objects experience the same acceleration.
d. There is not enough information given to determine the greater acceleration.
Questions 5 and 6
A railroad car runs under a funnel that loads sand onto the car as it moves.

5. What will happen to the momentum of the car as sand is loaded onto it?
a. The momentum will increase because of the added mass.
b. The momentum will decrease because the car will move more slowly.
c. The momentum will stay the same. The extra mass will be compensated for by the loss of velocity.
d. It is impossible to determine the effect on momentum from the information given.
6. What will happen to the velocity of the railroad car?
a. The velocity will increase to compensate for the added mass.
b. The velocity will decrease because of the increased mass.
c. The velocity will remain the same as the car is loaded with sand.
d. It is impossible to predict the effect on the velocity from the information given.
7. A baseball traveling at 35 m/s is hit by a bat and reverses direction. The velocity of the baseball after being hit is 52 m/s in the opposite direction. What is the Δv of the baseball?
a. 17 m/s
b. -17 m/s
c. -87 m/s
d. 87 m/s
8. What is the velocity of a 6 kg ball with 79.2 kg • m/s of momentum?
a. 475 m/s
b. 0.076 m/s
c. 13.2 m/s
d. 72.2 m/s
9. A force of 439 N acts on a ball for 0.77 s. What is the impulse delivered to the ball?
a. 570 N • s
b. 338 N • s
c. 5.7 N • s
d. 438 N • s
10. What is the change in momentum experienced by the ball in question #9?
a. 570 kg • m/s
b. 338 kg • m/s
c. 5.7 kg • m/s
d. 438 kg • m/s
Questions 11-14
A cart is set in motion. After the cart is already moving, describe the effect of the indicated change. The cart resets to its original mass and velocity inbetween each problem.
11. What will happen to the velocity of the cart if its mass is suddenly doubled?
a. Velocity will also double.
b. Velocity will remain the same.
c. Velocity will be reduced to ½ its original value.
d. The change in velocity is unpredictable.
12. What will happen to the momentum of the cart if its mass is suddenly doubled?
a. Momentum will also double.
b. Momentum will remain the same.
c. Momentum will be reduced to its original value.
d. The change in momentum is unpredictable.
13. What will happen to the velocity of the cart if the mass is suddenly cut to 1/3 of its original value?
a. Velocity will triple.
b. Velocity will remain the same.
c. Velocity will be reduced to 1/3 its original value.
d. The change in velocity is unpredictable.
14. What will happen to the momentum of the cart if the velocity is suddenly tripled?
a. Momentum will also triple.
b. Momentum will remain the same.
c. Momentum will be reduced to 1/3 its original value.
d. The change in momentum is unpredictable.
15. A ball strikes a wall and reverses direction. The mass of the ball is 0.33 kg. It strikes the wall with a velocity of 4.6 m/s and leaves at the same speed in the opposite direction. How much impulse does the wall deliver to the ball?
a. 0 N • s
b. -1.52 N • s
c. 3.04 N • s
d. -3.04 N • s
16. A cannon is firmly mounted on a boat (ignore friction). The mass of the boat and cannon is 355 kg. A 28 kg ball is loaded into the cannon. The boat is initially motionless on the water. The ball is then fired from the cannon at a speed of 82 m/s. What is the velocity of the boat after the cannon ball is fired?
a. -6.47 m/s
b. 6.47 m/s
c. 5.99 m/s
d. -5.99 m/s
17. The 3 kg block traveling at 6 m/s strikes the stationary 7 kg block. After the collision, the velocity of the 3 kg block is 1.7 m/s. What is the final velocity of the 7 kg block?

a. 1.29 m/s
b. 4.3 m/s
c. 3.3 m/s
d. 1.84 m/s
18. The blocks collide as shown in the diagram. What is the final velocity of the 7 kg block?

a. 2.57 m/s
b. 6 m/s
c. 3.3 m/s
d. 1.84 m/s
19. The blocks collide and stick together as shown in the diagram. What is the final velocity of the two blocks after the collision?

a. 9.37 m/s
b. 4.01 m/s
c. 2.81 m/s
d. 1.08 m/s
20. The two blocks collide as shown in the diagram. What is the initial velocity of the 3 kg block?

a. 1.27 m/s
b. 3.21 m/s
c. 3.82 m/s
d. -6.13 m/s

2006-07-06 20:12:30 · 4 answers · asked by Anonymous

2006-07-06 18:40:16 · 12 answers · asked by abdullah m 1

2006-07-06 18:06:21 · 8 answers · asked by Anonymous

light???...tom science

2006-07-06 18:01:43 · 12 answers · asked by Anonymous

2006-07-06 17:55:42 · 11 answers · asked by Anonymous

2006-07-06 17:55:35 · 4 answers · asked by Anonymous

2006-07-06 17:18:05 · 4 answers · asked by Anonymous

Or did they just assume that? How do we know they don't propagate faster than light?

2006-07-06 16:39:24 · 7 answers · asked by virtualscientist01 2

2006-07-06 16:17:57 · 3 answers · asked by Luis C 1

2006-07-06 16:16:13 · 7 answers · asked by Luis C 1

2006-07-06 16:10:14 · 3 answers · asked by Anonymous

2006-07-06 15:47:41 · 16 answers · asked by wizard 4

Our pool was painted a darker color. The theory is the the darker colour will absorb more heat keeping the pool warmer.

2006-07-06 15:44:32 · 2 answers · asked by donald_trevor 1

Do you think that a singularity (infinate mass, etc..) is reachable?
If so, do you think that time could've started with a singularity? (Creation, stuff like that.)

I, personally, think that there is a higher power, and that we're kinda like a big experiment to God. He/She just got bored and decided to say "What the heck, let's see what these idiots will make of this!", and put all the stuff there to make a singularity.

N E wayz, what do you guys think?

Thanks!
Sheena

2006-07-06 15:17:16 · 3 answers · asked by Anonymous

I think that this was covered on myth busters but I don't have cable tv and missed the episode.

2006-07-06 15:14:42 · 15 answers · asked by ape54321 2

I'm plain ignorant in this matter, but I'm asking out of curiosity.

2006-07-06 15:07:22 · 7 answers · asked by Anonymous

water properties

2006-07-06 15:02:40 · 6 answers · asked by Decisiveliu 1

2006-07-06 15:02:37 · 14 answers · asked by camille l 1

2006-07-06 14:39:50 · 16 answers · asked by Mark H 1

if yes, how does it over come so much viscosity

2006-07-06 14:32:59 · 15 answers · asked by baboon 1