Physics - November 2007

a 4000 lb car is travelling at 40 mi/h when its brakes are applied and it skids to rest. The skidding tires experience a friction force about .80 times the weight of the car. How far does the car go before stopping? Take the motion to be along a straight line.

since i'm trying to find its distance. Do i use d = .5 at^2?

2007-11-18 11:24:03 · 1 answers · asked by Anonymous

creating a lower atmospheric pressure, how would surrounding air move?

2007-11-18 11:23:27 · 1 answers · asked by T 1

what do you expect the current to be when V = 0 and why?

2007-11-18 11:22:59 · 3 answers · asked by mibg 1

2 boxes having mass m1= 1.0 and m2 = 2.0 kg are in contact with each other on a horizontal table. Friction between each block and the table is negligible. A horizontal force F is applied to m1, causing the blocks to accelerate to the right with a= 5.0 m/s^2.

a) What is the magnitude of F?

b) What are the forces of compression between the blocks?

2007-11-18 11:20:28 · 2 answers · asked by Anonymous

A) Sum the forces in x-direction. What is the value if the frictional force opposing the motion?

B) Sum the forces in y-direction. What is the value of the normal force?

2007-11-18 11:15:30 · 1 answers · asked by jeffery123456 1

1)Calculate the magnitude of the resultant of a pair of 80 km/h velocity vectors that are at right angles to each other.


2)What are the horizontal and vertical components of a 12 unit vector that is oriented 56° above the horizontal?

3)Calculate the magnitude of the horizontal and vertical components of a vector that is 140 units long and is oriented at 50° from the horizontal.

4)What are the horizontal and vertical components of a 13 unit vector that is oriented 38° above the horizontal?

2007-11-18 10:56:54 · 1 answers · asked by eaglesblueflag 1

Thanks in advance!

2007-11-18 10:47:37 · 1 answers · asked by big zach!!!! 2

A cylinder with a 16-cm-diameter piston contains gas at a pressure of 3.0 atm.
Part A
How much force does the gas exert on the piston?
Part B
How much force does the environment exert on the piston?
Part C
The gas expands at constant pressure and pushes the piston out 10 cm. How much work is done by the environment?
Part D
How much work is done by the gas?

2007-11-18 10:34:38 · 1 answers · asked by Anonymous

The intensity of sunlight that reaches the Earth's atmosphere is about 1500 W/m2. What is the intensity of the sunlight that reaches Jupiter? Jupiter is 5.3 times as far from the sun as Earth. [Hint: Treat the Sun as an isotropic source of light waves.]

W/m2

2007-11-18 10:28:38 · 3 answers · asked by sportzblock 1

2007-11-18 10:21:37 · 11 answers · asked by bthat 1

2007-11-18 10:08:05 · 32 answers · asked by Anonymous

2007-11-18 10:03:37 · 3 answers · asked by Anonymous

The question is that there is a frictionless incline and the angle of inclination is 20 degrees, and the spring constant is 331N/m and the mass of the block is 7 kg. The block is released from rest with the spring initially unstretched and the acceleration of gravity is 9.80 m/s^2. I tried to draw a picture so it would look like an acute triangle and a rectangle put together and the block would be on the part of the acute triangle and there would have to be a pulley where the acute triangle and rectangle meet. So I think I have to find the distance between where the acute triangle and rectangle meet to the distance where the block traveled. How can I find how far it travels down the incline before coming to rest and is my diagram okay?

2007-11-18 10:01:09 · 1 answers · asked by KE 1

Often times there are large red, or yellow "spheres", or "balloons" on electric transmission lines. What are these objects, and what is there purpose?

2007-11-18 09:58:16 · 3 answers · asked by Robert B 1

A 25 g bullet strikes and becomes embedded in a 1.55 kg block of wood placed on a horizontal surface just in front of the gun. If the coefficient of kinetic friction between the block and the surface is 0.45, and the impact drives the block a distance of 9.5 m before it comes to rest, what was the muzzle speed of the bullet?

__________m/s

2007-11-18 09:56:49 · 1 answers · asked by hayleym425 2

Nobel laureate Richard Feynman (1918-1988) once said that if two persons stood at arm's length from each other and each person had 1% more electrons than protons, the force of repulsion between them would be enough to lift a "weight" equal to that of the entire Earth. Carry out an order-of-magnitude calculation to substantiate this assertion.

the answer is ~10^26N, but i don't know how to get this number.

2007-11-18 09:52:11 · 1 answers · asked by andrew w 1

Need some help with this:
10 square blocks, each of mass 1kg are to be stacked up on a floor to make a piloe 50cm high - assuming that the block are initially all lying on the floor and assuming they have the same dimensions, how much work is done in stacking up the bricks.

Can anyone help me with some guidance please!

2007-11-18 09:46:36 · 1 answers · asked by Anonymous

I have a couple of math problems that I believe are interrelated with physics, and I'm not really sure how to solve these problems.

A person drops a ball onto the dirt below. Use this position function to solve the problem: -16t^2 + (initial velocity)(time) + initial height

How high is the wall if the ball hits the dirt 3 seconds after the ball is dropped?

What's the velocity of the ball when it hits the ground?

Thank you very much for your help. I will give 10 points to the most correct answer.

2007-11-18 09:32:41 · 2 answers · asked by Celine 1

I have a science report due tomorrow, two page min. four page max. (typed) The subject is Motion and Force. This is a list of all the things that must be included in the report. I've pretty much got the first part done
1. Description of what motion and force is
2. Description of different types of speed and examples of each
3. Description of different types of force and examples of each
4. Newton's 3 Laws of motion and examples of each
5. Any other interesting facts about the subject

If you get info off a website, I need sources!
Please help, I left all my notes at school and I'm doomed without you all.
By the way, I'm only 15, so I don't need college level info.

2007-11-18 09:30:02 · 1 answers · asked by Haley-bug 3

A 23.0 kg box is released on a 37.0° incline and accelerates down the incline at 0.272 m/s2. Find the friction force impeding its motion.
____N
How large is the coefficient of friction?

2007-11-18 09:29:41 · 1 answers · asked by roofchelsea 1

I have a physics problem, seems simple but I am getting a different answer than the book.

Problem : A ball is kicked at 15m/s horizontally on a 45 deg hill. In how much time will the ball land on the ground?

Books answer is 5.1 sec. I don't know how they get this answer.

Thanks for the help in advance.

2007-11-18 09:20:10 · 1 answers · asked by KOTEHOK 3

Is is safe to skydive on the moon? Theoretical question.

2007-11-18 09:14:17 · 5 answers · asked by Anonymous

What happens to stop the water from going out again?

2007-11-18 09:09:22 · 1 answers · asked by Anonymous

The past has no real matter and neither does the future.

2007-11-18 04:04:25 · 2 answers · asked by Anonymous

Hello..okay so man-made light cast different colors, so what is the respective color of incandescent light and fluorescent light?

2007-11-18 03:46:30 · 4 answers · asked by TJ 1

When a 4.00 kg object is hung vertically on a certain light spring that obeys Hooke's law, the spring streches 2.50 cm . If the 4.00 kg object is removed , (a) how far will the spring stretch if a 1.50 kg block is hung on it , and (b) hoe much work must an external agent do to stretch the same spring 4.00 cm from its unstretched position ?

2007-11-18 03:32:15 · 2 answers · asked by Anonymous

i know they are conductors with appreciable resistance but do you know the exact name of such substances?

2007-11-18 02:48:37 · 6 answers · asked by lost... 5

As it stands, string theory is unproved, and perhaps unprovable, as it involves interactions at energy levels far beyond any we can handle. But to those versed enough in the language of mathematics to follow it, it is beautiful. And in its beauty, string theory is the heir to Einstein's primitive first attempts to produce a unified field theory. It is multidimensional and some versions include as many as 26 dimensions, with 15 or 16 curled up in a tiny ball. It is geometrical: the interactions of one multidimensional shape with another produces the effects we call forces, just as the "force" of gravity in general relativity is what we feel as we move through the curves of four-dimensional space-time. And it unifies, no doubt about it, in the math, at least, all of nature from quantum mechanics to gravity emerges from the equations of string theory.

2007-11-18 02:17:14 · 9 answers · asked by bobe 6

in the horizontal direction. IF the batter's combined reacion and swing times total .350, how long can the batter watch the ball after it has left the pitcher's han before making a decision to swing.

2007-11-18 02:06:18 · 1 answers · asked by someone 1

A 5.0-m-diameter garden pond is 0.400 m deep. Solar energy is incident on the pond at an average rate of 400W/m^2 . If the water absorbs all the solar energy and does not exchange energy with its surroundings, how many hours will it take to warm from 16.0 degrees C to 22.0 degrees C?

2007-11-18 01:54:01 · 2 answers · asked by gbutterfly339 1