Physics - October 2007

2007-10-17 23:08:54 · 2 answers · asked by Anonymous

i tried doing these problems but my teacher said i got them wrong and to re do them.. can someone help?

a stone is dropped from a cliff. after it has fallen 40 m, what is the stone's velocity?


and also

what is the average acceleration of a car tha tgoes from rest to 59 km/h in 9.0 seconds?



and the last one


a ball is thrown up with a velocity of 60 m/s
at what time will it have a velocity of 0 m/s?

ahh please help! i greatly appreciate it

2007-10-17 23:05:04 · 5 answers · asked by cocomademoiselle 5

2007-10-17 22:56:38 · 3 answers · asked by Anonymous

i need to know this..


pls

2007-10-17 22:35:35 · 2 answers · asked by rHaiN 1

If,
1 Y (gamma photon) = e- + e+ (pair production)

then why not e- + e- = 1 gamma photon instead of 2 ? (annihilation)

2007-10-17 22:30:24 · 2 answers · asked by Rick 2

2007-10-17 22:27:04 · 5 answers · asked by Mike A 1

why is the calculated values of the resistance (e.g. total resistance) different from the measured values (using a software)? is there any discrepancy between the calculated and measured values?

2007-10-17 22:12:45 · 2 answers · asked by oopsy 1

2007-10-17 21:11:49 · 12 answers · asked by Anonymous

How slow would an electron have to be traveling for its wavelength to be at least 1 micro meter???

2007-10-17 20:31:47 · 4 answers · asked by jack86 1

motion

2007-10-17 20:00:21 · 7 answers · asked by surrr 1

My son had an Algebra question he was unable to answer. We were also unable to locate an example in his book or on the internet.

The question is:
If a plane flew 200 km/hr one way and 300 km/hr for the return trip and the total trip took 6 hrs, how far did the plane go? Any help is appreciated.

2007-10-17 19:28:28 · 5 answers · asked by pneeb4 2

a wire is strung between a building and the ground, making a 30-60-90 triangle as shown. the wire is attached to the ground 14 feet from the building. how far up the side of the building is the wire attached?

2007-10-17 17:38:47 · 6 answers · asked by Anonymous

when you throw a ball in the air,the earth exerts a force on the ball and the ball exerts a force on the _____.

2007-10-17 17:14:43 · 3 answers · asked by Rose 1

A street is at an inclination of 38 degrees with respect to the horizontal. a wooden crate has a mass of 25 kg and is placed on this street. a force of 59 N must be applied to crate perpendicular to the pavement in order to hold crate. coefficient of static friction between crate and pavement is 0.599. what's the magnitude of the frictional force?

HELP! haha...

2007-10-17 17:06:37 · 1 answers · asked by Ella 2

Cart 1 is at rest initially, and has a spring bumper with a force constant of 610 N/m . Cart 2 has a flat metal surface for a bumper, and moves toward the bumper of the stationary cart with an initial speed = 0.68m/s . Assume that positive -axis is directed toward the direction of motion of cart 2.
a.) How much energy is stored in the spring bumper when the carts have the same speed?
b.) What is the final speed of the cart 1 after the collision?
c.) What is the final speed of the cart 2 after the collision?

2007-10-17 17:04:59 · 1 answers · asked by Nik 1

2007-10-17 16:57:59 · 20 answers · asked by Anonymous

The eye of a hurricane passes over Grand Bahama Island. It is moving in a direction 60.0° north of west with a speed of v1 = 37.0 km/h. Exactly three hours later, the course of the hurricane shifts due north, and its speed slows to v2 = 27.0 km/h, as shown in Figure 3-30. How far from Grand Bahama, in kilometers, is the hurricane 4.50 h after it passes over the island?

** for my answer i got 118 km the first time, the second time i got 104 km using tangent and finding the angle which i got 20 degrees and then used that to find the hypoteneuse.

2007-10-17 15:49:12 · 1 answers · asked by wonderer 1

are 200m higher in elevation than when you started. Assuming no friction, what force has your engine exerted to drive up this slope?

a. 7000n
b.12000n
c. 14000n
d. 20000n

2007-10-17 15:37:42 · 1 answers · asked by Anonymous

I think this has been asked before, but...

The metric of space-time is expanding, right? So, shouldn't time be expanding along with space? If time were to expand, would we notice at all, or would it take us longer think thoughts and to perceive everything, perfectly balancing out the effect from our perspective so that we didn't notice?

2007-10-17 15:13:20 · 7 answers · asked by Anonymous

An atom is a mere millionth-trillionth-trillionth of a cubic meter in volume (0.000000000000000000000000000001 cubic meter).The solar system is a thousand-trillion-trillion cubic meters in volume (1,000,000,000,000,000,000,000,000,000).How many atoms could fit, tightly packed,into an object the size of the solar system?

2007-10-17 14:56:09 · 2 answers · asked by Anonymous

Ok, so I'm ion that part of our life when we gotta choose our future. So, I'm here to find out a little bit more about one of my biggest options (actually the biggest): Physics.
Although I love the subject on its own, - specially all the waves, colours, sound, etc. - I have no idea on what is to be a physicist.
I wanted to find out:
-What kind of jobs there are available after you graduate
-When do I've to choose (If I do) my sub-physic
-How is the carreer itself.

I'd really apriciate any kind of information you can give me, so please don't be shy, and if you know something, post it.

Thanks a million to everyone that can help me :) .

2007-10-17 14:54:59 · 5 answers · asked by Sebolains 2

A person walks 100m E, then 280 m S, then he walks 150.0 m at a 30.0 S of W, and then 200.0 m and a 60.0 angle north of west. what is the person's resultant displacement measured from the starting point?

2007-10-17 14:54:48 · 1 answers · asked by Maddi J 2

The coefficients of static and kinetic friction between a 559 crate and the warehouse floor are 0.665 and 0.420, respectively. A worker gradually increases his horizontal push against this crate until it just begins to move and from then on maintains that same maximum push.

What is the acceleration of the crate after it has begun to move?

Please show steps on how to work.

2007-10-17 14:45:56 · 1 answers · asked by Anonymous

The flake-bowl contact is frictionless.
(a) How much work is done on the flake by its weight during the flake's descent to the bottom of the bowl?
J
(b) What is the change in the potential energy of the flake-Earth system during that descent?
J
(c) If the potential energy is taken to be zero at the bottom of the bowl, what is its value when the flake is released?
J
(d) If, instead, the potential energy is taken to be zero at the release point, what is its value when the flake reaches the bottom of the bowl?
J

2007-10-17 14:43:04 · 1 answers · asked by tosinjesu 1

We did a "group" activity on a field trip I went on recently, and my Chem teacher is having me write a paper on it for that days credit. We had pipes that were cut longways and were rolling the golf ball down those. What would be a good topic (as in a science related topic) to write about useing this experence?

2007-10-17 14:41:25 · 1 answers · asked by T.K. 2

Four forces act on a hot-air balloon with F1 = 1690 N and F2 = 5020 N Find the magnitude and direction of the resultant force on the balloon.

2007-10-17 14:31:30 · 2 answers · asked by maxk222 1

Give an example where the knowledge of the difference in the coefficients of thermal expansion of different materials would be required.

2007-10-17 13:43:52 · 1 answers · asked by Anonymous

A 8.70 mass hanging from a spring scale is slowly lowered onto a vertical spring, as shown in the figure. Spring Constant=2650 N/m. At what compression length will the scale read zero?

2007-10-17 13:29:05 · 1 answers · asked by gbutterfly339 1

Is it possible?

2007-10-17 13:28:48 · 7 answers · asked by Noel B 2

A 20 kg child is on a swing that hangs from 3.0-m-long chains. What is her maximum speed if she swings out to a 45 degree angle?

2007-10-17 13:27:30 · 3 answers · asked by gbutterfly339 1