Physics - December 2007

You know how sometimes when you sneeze or something the numbers on a digital clock look like they're moving? Like all of the lines that make them up move away from each other. Why is that?

2007-12-03 14:51:05 · 3 answers · asked by spuality 2

Why does no critical angle exist for light traveling from a fast (less dense) medium into a slow (more dense) medium?

2007-12-03 14:31:22 · 3 answers · asked by jayne2 3

i need this by tonight, its my science hw!! if i dont give this question ibn tomorrow i get 33.3 points of... some one help me plzz...

2007-12-03 13:35:52 · 4 answers · asked by gsli4ever 2

A 2.2 kg cylinder (radius = 0.12 m, length = 0.50 m) is released from rest at the top of a ramp and allowed to roll without slipping. The ramp is 0.81 m high and 5.0 m long.
(a) When the cylinder reaches the bottom of the ramp, what is its total kinetic energy? 17.4J
(b) What is its rotational kinetic energy? ?J
(c) What is its translational kinetic energy? ?J
Please help me on paarts b&c

2007-12-03 13:27:13 · 1 answers · asked by Anonymous

A 20 g rifle bullet traveling 225 m/s buries itself in a 3.9 kg pendulum hanging on a 2.5 m long string, which makes the pendulum swing upward in an arc. Determine the horizontal component of the pendulum's displacement.
In meters

2007-12-03 13:13:40 · 1 answers · asked by joe s 1

I know this is really simple but I forgot what it would be.
(I have a review test tomorrow from stuff we learn awhile ago)

When the angle of incidence increases the angle of refraction...?

Increases Remains the same
Decrease cannot be determined

Thanks for your help.

2007-12-03 12:50:28 · 1 answers · asked by Anonymous

How high does a rocket have to go above earth's surface before its weight is half what it would be on Earth?

Ok, before "Justin" or any other idiot gets on here and says "omg this is cheating ,blah blah" it's not cheating my class is different from her/his and we already have all the answers, but I really want to know how to do it! Mrs Luca explained it to us but I didn't get it, so I'd like someone to clean it up for me step by step please???

2007-12-03 12:46:05 · 2 answers · asked by E 2

a ball moving at 5m/s strikes a stationary ball of the same mass
the first ball moves at an angle of 30 degrees relative to th origional line of motion
the second ball moves at an angle of 90 degrees with respect to the final path of the first ball
find the velocity (magnitude and direction) of the second ball after contact
is this elastic or inelastic
explain and show work plz

2007-12-03 12:33:06 · 1 answers · asked by confused 1

2007-12-03 12:26:39 · 1 answers · asked by lady_wolf_sushi 2

a ball moving at 5m/s strikes a stationary ball of the same mass
the first ball moves at an angle of 30 degrees relative to th origional line of motion
the second ball moves at an angle of 90 degrees with respect to the final path of the first ball
find the velocity (magnitude and direction) of the second ball after contact
is this elastic or inelastic
explain and show work plz

2007-12-03 12:22:40 · 1 answers · asked by confused 1

I'm taking a Physics class this year, but I've become really lost in our current chapter. Before I request aid from the teacher, I was wondering how well some of you can help me. What is centripetal acceleration? How does it work? How is it different from tangential (linear) acceleration? What are the varibles connected to it (like alpha "a") and what they represent? What are the formulas used to find things in Centripetal acceleration? Can you give me a sample problem, with the answer to be found below it?

2007-12-03 12:10:47 · 0 answers · asked by Anonymous

for a physics assignment help me out people

2007-12-03 12:08:20 · 1 answers · asked by Kyle R 1

for a physics assignment help me out people

2007-12-03 12:07:18 · 1 answers · asked by Kyle R 1

Ok, I'm at a loss for how to figure this out.

There's a rope and pulley system with two blocks. The first block (M1) is attached to a rope above the ground. The second (M2) is on a ramp incline.

Ramp angle is at 20º
Ramp is high enough for M1 to fall 4 meters before hitting ground.
Mass M2 is 100 kg

Static coefficients of M2 are:
Static friction = 0.35
Kinetic friction = 0.30.

Also assume we have an "ideal" rope (no mass and doesn't stretch) and "ideal" pulley (no mass or friction).

So, my question: What does the mass of M1 have to be in order for M2 to move up the ramp? In addition, what is the velocity of M2 when M1 hits the ground?

Equations, descriptions, ANYTHING will help at this point. Thanks!

2007-12-03 11:29:39 · 1 answers · asked by Anonymous

given mass of the earth,moon and the distance between the earth and the moon as 3.8*10^8.....

2007-12-03 11:25:16 · 1 answers · asked by lp342 4

Since gravity pulls you down. So the object in Earth's orbit is trapped there because gravity is pulling it toward the center of the planet. Right???????????????????????????????????

2007-12-03 11:14:41 · 2 answers · asked by sam007mama 1

please do the same with 10 lb 20lb 6ft and 7 ft

2007-12-03 11:11:29 · 3 answers · asked by ShortCircuit 2

A tire contains air at a gauge pressure of 33.8 lb/in^2 at a temperature of 30.9 C. After nightfall, the temperature drops to -12.9 C. Find the new gauge pressure in the tire, assuming that the volume of the tire remains constant during this process in units of lb/in^2.

1 atm=14.7 lb/in^2

2007-12-03 11:10:41 · 1 answers · asked by snow200098 2

before you step your momentum is zero then you step and now you have some momentum.
is the principles of conservation of momentum violated?
Explain
i think the answer is no but i dont know how to explain it

2007-12-03 11:05:09 · 5 answers · asked by confused 1

Determine the force on -e (choose any -e in the diagram)
(the shape is square and the edges is 0.1m.)
+e----------(-e)
...l.................l
...l.<-0.1m->l
...l.................l
(-e)---------+e
thanks.p.s. dont mind the dots.

2007-12-03 10:49:47 · 1 answers · asked by Ross 1

Physics homework... :(

2007-12-03 10:43:36 · 3 answers · asked by David F 1

you push a 325-N trunk up a 20 degree inclined plane at a constant velocity by exerting a 211-N force parallel to the planes surface. What is the sum of all forces parallel to the planes surface?
Can someone explain how to solve this?

2007-12-03 10:42:43 · 1 answers · asked by Aitu4 3

A 3.2-kg block is hanging from the end of vertical spring that is attached to the ceiling. The elastic potential energy of this spring/mass is 1.8 J. What is the elastic potential energy of the system when the 3.2-kg block is replaced by a 5.0-kg block?

2007-12-03 10:34:43 · 1 answers · asked by phyStudnt 1

A careless driver rear-ends a car that is halted at a stop sign. Just before the impact, the driver slams on his brakes, locking the wheels. The driver of the struck car also has his foot on the brake pedal, locking his wheels. THe struck car has a mass of 900 kg, that of the initially moving car is 1200kg. On collision, the bumpers of the 2 cars stick together. The sliding cars leave marks 0.760m long. Tests show that the coefficient of kinetic friction btw tires and pavement is 0.920. What is the velocity of the moving car as he approached the intersection?

2007-12-03 10:33:26 · 2 answers · asked by Anonymous

A long wire carrying a current of 1A runs along the x-axis & takes a circular detour in the x-y plane of a radius 5 cm. Whats is the magnitude & direction of the resultant magnetic field at a distance of 5 cm above the center of the circle?? someone please help...thanks in advance :)

2007-12-03 10:27:40 · 2 answers · asked by a.n. 1

Bohr's ideas about electron orbits helped explain the regularity of atomic spectra but did not explain why the electron should orbit the nucleus only at certain distance. How did De Broglie's ideas of the dual nature of matter help explain the quantized orbits of electrons in atoms?

2007-12-03 10:26:43 · 1 answers · asked by David T 3

An 85 kg fisherman jumps from a dock into a 135 kg rowboat at rest on the west side of the dock. If the velocity of the fisherman is 4.3 m/s to the west as he leaves the dock, what is the final velocity of the fisherman and the boat.

A dry cleaner throws a 22 kg bag of laundry onto a stationary 9 kg cart. The cart and laundry bag begin moving at 3 m/s to the right. Find the velocity of the laundry bag before the collision.

2007-12-03 10:01:33 · 2 answers · asked by Doc. Ock 3

1. A monatomic ideal gas ( = 1.67) is contained within a box whose volume is 5.0 m3. The pressure of the gas is 7.00 105 Pa. The total mass of the gas is 2.5 kg. What is the speed of sound in the gas?

2. Suppose that sound is emitted uniformly in all directions by a public address system. The intensity at a location 26 m away from the sound source is 3.50 10-4 W/m2. What is the intensity at a spot that is 76 m away?

3.You are riding your bicycle directly away from a stationary source of sound and hear a frequency that is 2.5% lower than the emitted frequency. The speed of sound at the temperature that day is 350 m/s. What is your speed?

4.A 3.49 rad/s (33 1/3 rpm) record has a 3.00 kHz tone cut in the groove. If the groove is located 0.090 m from the center of the record (see drawing), what is the "wavelength" in the groove?

2007-12-03 10:00:23 · 1 answers · asked by Anonymous

2007-12-03 09:52:30 · 4 answers · asked by Pooter 1

2007-12-03 09:50:36 · 5 answers · asked by Anonymous