Physics - December 2007

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PLEASE EXPLAIN BRIEFLY AND LABEL ANSWERS!
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A helium balloon rises upward at rate of 7.0 metres/second, to a height of 20 m before it pops. A steady breeze of 1.5 m/s due east blows against the balloon.

A) What is the velocity of the balloon relative to the ground?

B) How long does it rise before popping?

C) How far from its starting point has it flown (final displacement)?

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A firefighter climbs up 10.0 m ladder leaning against a vertical wall. The ladder makes an angle of 20 degrees with the wall. The firefighter reaches the roof in 15.0 s.

A) What is the height of the wall?

B) How far is the base of the ladder from the wall?

C) What is the firefighter's average vertical velocity?

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Suzanne is skiing with a velocity of 18.0 m/s [N30.0 degrees W]. What is the [N] component of her velocity vector?

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Tim is running cross-country at 6.4 m/s [S] when he completes a wide turn and continues at 5.8 m/s [W]. What is his change in velocity?

2007-12-07 07:59:03 · 1 answers · asked by Deloris 1

2 objects one with as mass 0f 10 kg and the other with 17kg each with a charge of -.013C. separated by 9 m

what is the electric force they exert on each other?
gravitational force?

2007-12-07 07:02:20 · 5 answers · asked by sweetishfishy75 1

Given the fact that I'm a laymen (layman?) and don't have a science education past my college freshman year (intro) physics class, little help on understanding it? I get the concept, but what exactly IS it? How would it be employed to (supposedly) generate great deals of energy (sue me, I like Star Trek)?

2007-12-07 06:52:27 · 8 answers · asked by Skalite 6

2007-12-07 06:32:07 · 4 answers · asked by Michael M 4

2007-12-07 05:52:55 · 6 answers · asked by brenden j 1

Cars used to be built as rigid as possible to withstand collisions. Today, though, cars are designed to have "crumple zones" that collapse upon impact. What is the advantage of this new design?

2007-12-07 05:49:58 · 7 answers · asked by jo8 1

The current philosophy is uncertainty principle.
Has anybody actually meaured a statistical variation on the speed of light?
At what point from quantum level up does uncertainty arise?
The concept of introduction of uncertainty seems to be a given rather than explanation and the parameters that may attribute to it seem to be rather fixed.
Has anybody tried to ascertain the point at which uncertainty is inherent and written any papers on it?

2007-12-07 05:48:24 · 6 answers · asked by interested_party 4

Swimmers starting from rest slide down from the top of a slide and leave the end of the slide traveling horizontally. A person hits the water 5.00 m from the end of the slide in a time of .500 seconds after leaving the slide. Ignoring air resistance and friction, find the height.

A block has a mass of 2.0 kg sliding on a frictionless surface toward a relaxed spring of lenght .30 m. When striking the spring the block continues to slide to the right until the spring is squeezed down to a length of .10 m, at which the block momentarily comes to rest. if the block's initial speed is 10.0 m/s, what is the average force exerted by the spring in brining the block back to rest? Use the impulse-momentum theorem to estimate the time it took to stop the block, from the moment it first came into contact with the spring until it came to rest.

2007-12-07 05:46:09 · 4 answers · asked by jdowgg88 1

sure there's the wind factor but what else

2007-12-07 05:06:11 · 6 answers · asked by Anonymous

the earth rotates at a speed of about roughly 1000 miles per hour in the equator, thats close to 444 meters per second. Now if I stand in the equator and throw a baseball vertically up in the air, why doesnt' it land on the earth 444 meters away from me(after a second). Because all this time, only i was in contact with the earth, so only i should move, the ball in the air shouldn't move. Ok, granted, lets take air currents etc into consideration, but still i'm moving away from the ball at 444 meters per second, even if we take the currents into consideration, the ball should atleast fall a 100 meters away from me. Why doesnt' this happen? and finally Why can't we just levitate in air, and use earth's rotation to travel?

2007-12-07 04:40:01 · 6 answers · asked by swamy g 1

2007-12-07 04:39:57 · 4 answers · asked by jessabug2005 1

if i had a circle with a radius of six and a force aplied to the tangent of the cirlce of 10N then there would be a Torque 60 NM if this was aplied constatly would the rotational speed of the circle increase? and if so how whould i calculate this. if you cuold email me @ anubis2652@yahoo.com it would be great.

2007-12-07 04:33:19 · 2 answers · asked by anubis2652 1

2007-12-07 03:20:11 · 4 answers · asked by Janette M 1

2007-12-07 03:19:16 · 2 answers · asked by Sabrina T 1

They have nothing to do with pressure OR temperature--so Im inclined to think that they dont know what the hell they're talking about.

2007-12-07 03:12:48 · 6 answers · asked by Anonymous

2007-12-07 00:01:53 · 6 answers · asked by Anonymous

A 0.250-kg coffee cup at 20 degrees C is filled with 0.250 kg of boiling coffee. The cup and the coffee come to thermal equilibrium at 80 degrees C. If no heat is lost the environment, what is the specific heat of the cup material? [Hint: Consider the coffee essentially to be boiling water.]

2007-12-06 22:03:26 · 3 answers · asked by Anonymous

2007-12-06 20:41:32 · 5 answers · asked by Anonymous

2007-12-06 20:35:51 · 14 answers · asked by Anonymous

2007-12-06 20:28:53 · 2 answers · asked by knowledge hunter 1

2007-12-06 20:19:54 · 2 answers · asked by knowledge hunter 1

A point charge q1 is at the origin and second point charge q2 is at infinity. Use a three dimensional system to answer this problem. (x,y and z).

2007-12-06 19:57:10 · 1 answers · asked by duntoktomee 2

1. On a see-saw mass A is 60 kg
and is 1 m from the pivot. Mass B is 30 kg
and mass C is 10 kg. Mass C is 3 m from
the pivot. The see saw is at an angle of 30
degrees from the horizontal. Calculate the
torques of A and C about the pivot and
where you should place mass B for the
torques to balance.



2. As part of a physical therapy program
following a knee operation, a 5-kg object is
attached to an ankle and leg lifts are done as
sketched in the figure. Calculate the torque
about the knee due to this weight for the four
positions shown. from the knee to the weight is 40 cm
the four positions are at 0, 30, 60, 90 degrees.

2007-12-06 19:46:20 · 2 answers · asked by bebop1223@sbcglobal.net 2

A 4.00-g bullet is fired with a velocity of 96 m/s toward a 10.00-kg stationary solid block resting on a frictionless surface.

(a) What is the change in momentum of the bullet if it is embedded in the block?
kg·m/s
(b) What is the change in momentum of the bullet if it ricochets in the opposite direction with a speed of 95 m/s-almost the same speed as it had originally?
kg·m/s

2007-12-06 19:32:31 · 1 answers · asked by Nicky 1

A string of length L vibrates at its fundamental frequency. The amplitude at a point (1/4)L from one end is 4.10 cm.

What is the amplitude of each of the traveling waves that form this standing wave?


* Can someone help me figure out how to solve this???

2007-12-06 19:24:01 · 3 answers · asked by Professor 1

Europa, a satellite of Jupiter, appears to have an ocean beneath its icy surface. Proposals have been made to send a robotic submarine to Europa to see if there might be life there. There is no atmosphere on Europa, and we shall assume that the surface ice is thin enough that we can neglect its weight and that the oceans are fresh water having the same density as on the earth. The mass and diameter of Europa have been measured to be 4.78×1022 kg and 3130 km, respectively.

If the submarine intends to submerge to a depth of 110 m, what pressure must it be designed to withstand?

If you wanted to test this submarine before sending it to Europa, how deep would it have to go in our oceans to experience the same pressure as the pressure at a depth of 110 m on Europa?

2007-12-06 18:31:03 · 1 answers · asked by ! 2

For physics we are doing a project and I need help with finding a way to either stop the bowling ball before it impacts the egg, redirect th bowling ball away from the egg, or make a contraption to push the egg out of the bowling balls way. We are only given these materials:
-150 toothpicks
-6 long skewer sticks
-5 sets of chopsticks
-10 glue sticks
-1 manila folder
Here are the requirments:
a. With the exception of saran wrap the egg doesn't have anything else touching it.
b. As far as the egg goes: no leakage
c: Only materials given can be used
d. Wherever the egg is located the bowling ball must be directly over it
Some important information is that the bowling ball is 14 lbs and will be lifted two meters directly above the egg.

So how do you keep it from leaking??

2007-12-06 18:16:49 · 6 answers · asked by Anonymous

A 4.10 kg silver ingot is taken from a furnace, where its temperature is 747degrees C, and placed on a very large block of ice at 0.00 degrees C. Assuming that all the heat given up by the silver is used to melt the ice and that not all the ice melts, how much ice is melted?

2007-12-06 18:02:56 · 4 answers · asked by ! 2

A 2.0-kg block sliding on a rough horizontal surface is attached to one end of a horizontal spring (k = 250 N/m) which has its other end fixed. The block passes through the equilibrium position with a speed of 2.6 m/s and first comes to rest at a displacement of 0.20 m from equilibrium. What is the coefficient of kinetic friction between the block and the horizontal surface?

2007-12-06 16:38:59 · 4 answers · asked by roncho 4

Anybody know how to do this? I need help/ an answer ASAP! THANKS (:

2007-12-06 16:35:34 · 2 answers · asked by Anonymous