Physics - February 2007

A curve with a 120-m radius on a level road is banked at the correct angle for a speed of 20 m/s.

If an automobile rounds this curve at 30 m/s, what is the minimum coefficient of static friction between tires and road needed to prevent skidding?

2007-02-11 17:27:47 · 2 answers · asked by M 1

A box of mass m rests on the flat floor of a truck. The coefficients of friction between the box and floor are µ_s and µ_k. The truck stops at a stop sign and then starts to move with an acceleration of a.

If the box is a distance x from the rear of the truck when the truck starts, how much time elapses before the box falls off the truck?
Take the free fall acceleration to be g .

How far does the truck travel in this time?
Take the free fall acceleration to be g.

2007-02-11 17:26:42 · 1 answers · asked by M 1

(a) If the coefficient of kinetic friction between tires and dry pavement is µk, what is the shortest distance in which an automobile can be stopped by locking the brakes when traveling at v?
Take the free fall acceleration to be g.

(b) On wet pavement the coefficient of kinetic friction may be only µ_wet . How fast should you drive on wet pavement in order to be able to stop in the same distance as in part (a)?

2007-02-11 17:23:58 · 1 answers · asked by M 1

2007-02-11 16:31:03 · 1 answers · asked by adictpunk04 2

Two astronauts, each having a mass of 75.0 kg, are connected by a 10.0 m rope of negligible mass. THey are isolated in space,orbiting their center of mass at speeds of 5.00 m/s. calculate
A)magnitude of the angular momentum of the system by treating astronauts as particles
and B) the rotational energy of the system. by pulling on the rope, the astronauts shorten the distance between them to 5.00m
C)what is the new angular momentum of the system?
D) what are their new speeds?
E) what is the new rotational energy of the system?
F) how much work is done by the astronauts in shortening the rope?

XD i have been working on it all weekend..and i cant get it..can someone help me figure it out please T_T

2007-02-11 16:27:50 · 2 answers · asked by Becky 2

then does that mean that the future is going to be dark? Just some food for thought.

2007-02-11 16:21:31 · 8 answers · asked by democrat13 2

2007-02-11 16:16:32 · 6 answers · asked by jimmy lie 1

Basically I am talking about space-time. I have heard people say that time is like the fourth dimension, but when we are talking about dimensions, aren't we talking about space? Einstein says that space and time are linked, so then it would seem to follow that there could still be 3 dimensions up/down (altitude), east/west (latitude), north/south (longitude), but the space it each direction is now linked to time. We just don't notice the link because we are not traveling close enough to the speed of light (or fast enough).

2007-02-11 16:16:01 · 5 answers · asked by Wonderer 1

Ok, heres the question-

A hydrogen molecule consists of two hydrogen atoms whose total mass is 5.3 10-26 kg and whose moment of inertia about an axis perpendicular to the line joining the two atoms, midway between them, is about 1.94 10-46 kgm2. Estimate, from these data, the effective distance between the atoms.

2007-02-11 15:55:25 · 2 answers · asked by Churro 2

Problem 1: When 18 seconds elapse on a clock on the alien spaceship traveling at 4/7, how much time elapses on Earth clocls according to Earth observers?

Problem 2: The aliens observe an experiment on Earth as they fly by at a speed of 4/7. If Earth observers measure the duration of the experiment to be 30 seconds, what will be the duration of the experiment according to the alien observers?

2007-02-11 15:51:59 · 4 answers · asked by Anonymous

Specifically, how does it work for light? Does it need an aperture (small slit) to work?

2007-02-11 15:22:45 · 3 answers · asked by Angelfire 2

What are some examples of Newton's third law?

2007-02-11 15:12:08 · 18 answers · asked by Anonymous

it be affected by a centripital force if it encountered one? Thanks for your time

2007-02-11 15:11:15 · 3 answers · asked by Buck BUCK 2

Our world is a sphere.
But, what if the explorers back then were right?
What if our world were cubical?
How do you think would it affect the climate, the animals, nature...

What's your opinion?

2007-02-11 14:55:18 · 1 answers · asked by Anonymous

I'm doing a project on the principles that Galileo has discovered in the field of physics. I was wondering if I had missed any that anyone knew of. So far I have:
1) his work on pendulums
2) theory of motion and unifrom acceleration
3) work on inertia
4) parabolic fall
Anything else? Also, any ideas for a good model? It can't be a poster or something restating our paper, she's looking for an application or reenactment of one of his experiments.

2007-02-11 14:42:51 · 1 answers · asked by Anonymous

2007-02-11 14:20:29 · 10 answers · asked by ................................ 2

2007-02-11 14:18:24 · 5 answers · asked by ................................ 2

A 4 g CD has a diameter of 12 cm. If its angular speed is 200 RPM, determine the centripetal acceleration of the CD as it spins and the centripetal force acting on the CD? Please help as soon as possible!

2007-02-11 14:15:52 · 1 answers · asked by Anonymous

The circuit in the drawing shows two resistors, a C = 6.5 µF capacitor, and a V = 18 V battery. When the capacitor is fully charged, what is the magnitude q (in Coulombs) of the charge on one of its plates?

where R1 = 4 ohms and R2 = 2 ohms and are in series to each other and the capacitor is drawn in parallel w/ the 4 ohm resistance

2007-02-11 14:13:49 · 4 answers · asked by christian m 2

2007-02-11 13:44:39 · 4 answers · asked by sochn9022jkl 1

Deflection of Electrons in an Electric Field

2007-02-11 13:39:02 · 1 answers · asked by Robby B 1

i have 2 questions...

A 2 kg rock is suspended from the tip of a meter stick at the 0 cm mark so that the meter stick is balanced like a see saw when the fulcrum is at the 25 cm mark. From this info, what is the mass of the meter stick?

What causes a ball to roll down a hill? is it rotational inetia?

2007-02-11 13:37:46 · 2 answers · asked by globesk8er999 1

A 0.98kg rock is projected from the edge of the top of a building with an initial velocity of 12.4m/s at an angle 60degree above the horizontal . due to gravity, the rock strikes the ground at a horizontal distance of 17m from the base of the building.
Assume: the ground is level and that the side of thr bulding is verticle. the asseleration of gravity is 9.8m/s2

2007-02-11 13:08:27 · 3 answers · asked by i.p 1

put the number next to the answer. please

1. who is created with being the sceintest who developed the perodic table
2. what is the density of a chunk of gold that weighs 2.00kg? its volume is 10.6cm cubed
3. the density of gasline at 20*c is .7 g/ml. what is the mass of 3.56 liters of gasoline?
4. ice has a density of .92g/cm cubed, what is the volume of 25g of ice

2007-02-11 13:05:05 · 3 answers · asked by ititit3 2

A common flashlight bulb is rated at 0.2A and 2.9V. If the resistance of the bulb's tungsten filament at room temperature (20°C) is 1.10Ω, estimate the temperature of the tungsten filament when the bulb is turned on.

2007-02-11 13:04:54 · 4 answers · asked by brilliantdance12 1

A hiker begains a trip by first walking 24.7 km SouthEast from her base camp. On the second day, she walks 42.3 km in a direction 64.8degree north of east, at which point she discovers a forest ranger's tower.
--Determine the y compnent of the total displacement. Answer in
km
--Find the magnitude of the resultant displacement. answer in km
--Find the angle θ that the vector R=A+B makes with the positive
x-axis, use the counterclockwise as the positive angular
direction, between the limits of -180 and +180. answer in
degree

2007-02-11 13:00:58 · 1 answers · asked by i.p 1

thx for the help

2007-02-11 12:57:15 · 12 answers · asked by navratna s 1

- I am an extremely accomplished high school senior, and a potential presidental scholar. I have conducted research in medicine (specifically skin cancer), but not my most avid interest, theoretical astrophysics and theoredical physics. I have already, early on, completed honors and AP physics. Where can a high school senior go to conduct research on such theoretical physics?

2007-02-11 12:50:50 · 2 answers · asked by Anonymous

First can you define a chemical property?

And what is the difference between a chemical property and a physical property. Thanks alot!

2007-02-11 12:46:19 · 5 answers · asked by ? 2

vector A has magnitude of 8 and points in the positive x-direction. Vector B has magnitude of 23 and makes an angle of 39degree with the positive x-axise

--- What is the magnitude of A-B

2007-02-11 12:45:49 · 3 answers · asked by i.p 1