Physics - September 2007

"A car is traveling at 45m/s and passes a truck. Two seconds later and with acceleration (2 m/s^2) the truck starts after the car. How long in seconds does it take to catch the car?"

I think it might be 32.7 seconds. Am I right?

2007-09-06 09:26:40 · 2 answers · asked by Kayla G 1

supposed I have a container that I can close entirely. Also suppose that we put some water into the container and leave the rest as air. Then we close the container and start to heat it.

What is the formula that governs the evaporation rate of the water and the total amount of water in vapor form? I would be very interested in the physics behind the derivation of the formula, so if someone can suggest a textbook or webpage, I would be much obliged.

thanks

2007-09-06 09:08:29 · 5 answers · asked by janbbeck 2

http://www.youtube.com/watch?v=UXY5hWOtgOI

2007-09-06 08:21:20 · 1 answers · asked by TD Euwaite? 6

2007-09-06 07:50:22 · 14 answers · asked by jtesn 1

i have a problem. a vector has an x-component of -25 units and y -component of 40.unit, find the magnitude and direction of this vector

i did this problem like
i drew from where they started to forward the left to get -25 units, then go up 40units
|
| 40 units
|
<-------------------
-25 units
magnitude is square root ((-25)^2 +40^2) = 47.2 units by pythagorean theorem

i have a diifficult to understand the angle , because i look the answer on the back i got the right answer but i dont know that is illegal method to do it

tan x = 40/-25
x = tan^-1 (40/-25) = -57.9

angle is 180+ - 57.9 = 122.1 degree
i dont know why i added 180 degree to that answer, please helps me out. thank you

2007-09-06 07:48:14 · 7 answers · asked by jennifer 2

2007-09-06 07:41:10 · 4 answers · asked by fcctom 1

partscoretotalsubmissions1--11/3An observer, whose eyes are 1.80 m above the ground, is standing 33.0 m away from a tree. The ground is level, and the tree is growing perpendicular to it. The observer's line of sight with the treetop makes an angle of 17.0° above the horizontal. How tall is the tree?

2007-09-06 07:24:30 · 1 answers · asked by Marianna E 1

i know what it is but how do i explain it?

2007-09-06 07:15:25 · 7 answers · asked by Anonymous

It would be a great help if you could help me!! Thanks.

2007-09-06 07:10:50 · 8 answers · asked by Anonymous

A jet is diving vertically downward at 1390 km/h. If the pilot can stand a maximum acceleration of 5g (i.e., five times the acceleration of gravity on Earth's surface) before losing consciousness, at what height must the plane start a quarter turn to pull out of the dive? Assume the speed remains constant.

2007-09-06 07:07:30 · 2 answers · asked by dsgdh 2

ok so now i have this question that i have been trying to figure out since yesterday and idk what they are wanting me to say im just not sure about this one. any help would be appreciated thank you!

2007-09-06 06:54:58 · 15 answers · asked by Anonymous

describe three exampes in velocity from sportsin which a force changes the velocity of an object or person.... i think i have one?
i said when a bat hits the baseball the ball changes in speed and direction.
is that correct? and if so i just need two more examples

2007-09-06 06:46:09 · 3 answers · asked by Anonymous

Huge icebergs can be seen only in small visible fraction. If the specific gravity of seawater and ice are 1.024 and .817, respectively, what is this fraction?

2007-09-06 06:29:22 · 2 answers · asked by physics maniac 2

Suppose you have 1A DC current flowing through 1 inch of straight wire. Physics textbooks always show circular, concentric magnetic lines around the wire at a cross-section "slice" of the wire where the direction of the lines is determined by the right-hand rule.

In reality, the lines extend across the entire length of the wire. So are the "lines" really discrete or are they continuous like a cylinder (length-wise) ? If not, then what's the distance between the lines along the length of the wire? Also, what's the distance between the concentric lines for a given cross-area?

I'm not even sure if these are meaningful questions but it'd help me to visualize what inductance really is (# of magnetic lines divided by current).

Thanks.

2007-09-06 05:51:21 · 6 answers · asked by ckrich_99 1

The position of a particle moving along an x axis is given by x = 15.0t^2 - 4.00t^3, where x is in meters and t is in seconds. Determine (a) What is the maximum positive coordinate reached by the particle and (b) at what time is it reached? (c) What is the maximum positive velocity reached by the particle and (d) at what time is it reached? (e) What is the acceleration of the particle at the instant the particle is not moving (other than at t = 0)? (f) Determine the average velocity of the particle between t = 0 and t = 3.00 s

2007-09-06 05:35:36 · 2 answers · asked by Tastytaint 1

2007-09-06 05:27:19 · 7 answers · asked by Anonymous

I know there's a lot of them out there. I wish to know which one you consider the best in terms of screen output and good interactive interface.

2007-09-06 04:59:35 · 2 answers · asked by 700BILLIONPOORER 3

from the top of a 35.3-m tall building. The ball then passes the top of a window that is 13.3 m above the ground 2.00 s after being thrown. What is the speed of the ball as it passes the top of the window?

2007-09-06 04:58:16 · 2 answers · asked by Fashionably lame 1

vertically upward from ground level at time t = 0. At time t = 1.6 s it passes the top of a tall tower, and 1.5 s later it reaches its maximum height. What is the height of the tower?

2007-09-06 04:57:24 · 1 answers · asked by Fashionably lame 1

2007-09-06 04:23:09 · 2 answers · asked by Mohshi 1

it's about the atomic bomb! i really don't understand what the hell was he thinking!

2007-09-06 03:19:36 · 4 answers · asked by TRUE-NERDY-BOY 1

I'm doing some self-research into black holes from a thermodynamic standpoint and I'm wondering, what's the minimum mass or combination of mass, pressure, density, etc. required to create a black hole?

2007-09-06 02:53:18 · 6 answers · asked by Hesacon 2

2007-09-06 01:24:05 · 4 answers · asked by worried person 1

For some reason when I switch signs, the answer is still incorrect. Math error? Also Find CCW Angle that b-a makes on positive x-axis?

2007-09-06 01:07:28 · 1 answers · asked by bouncing_soul_geuse 2

why do we need to harness more energy from renewable sources instead of non-renewable sources?

i'm asking this coz i don't really get the question.. hehe

2007-09-06 01:01:57 · 4 answers · asked by moose_uncanny 2

Based on a physics textbook, TORQUE is defined as a cross product between Force and Distance (T = F x D).

Scenario:
Given: a circular disc with a radius of 2 feet that is connected to a shaft (making them a single unit).

Question:
If the shaft is rotated with a Force of 10 pounds, and the edge of the disc is attached to another another disc with a similar shaft, what would be the output torque? 20 lb-ft? Please explain.

A simple illustration below. The figure represents the 2 discs with shafts (face opposite each other).

Force 10 lbs... --[ ]-- ...Torque at the other end?


Many thanks!

2007-09-06 01:01:04 · 2 answers · asked by Anonymous

2007-09-06 00:57:13 · 4 answers · asked by moose_uncanny 2

Looking for guidance.. I've arrived at the magnitude is 5.71cm, however I can't seem to visual the interval of the angle.

2007-09-06 00:48:22 · 2 answers · asked by bouncing_soul_geuse 2

2007-09-06 00:44:22 · 2 answers · asked by moose_uncanny 2

its for my homework.. if you know please help.. thank you in advance..

2007-09-06 00:37:44 · 5 answers · asked by moose_uncanny 2