Physics - December 2007

Not quite sure how to approach this problem.. not even really sure if I know which part the axle is.. any and all help is greatly appreciated.

A 12.0kg box resting on a horizontal, frictionless surface is attached to a 5.00kg weight by a thin, light wire that passes over a frictionless pulley (View Figure). The pulley has the shape of a uniform solid disk of mass 1.50kg and diameter 0.540m.

After the system is released, find magnitude of the horizontal and vertical components of the force that the axle exerts on the pulley.

btw.. the moment of inertia for a disk is I=(MR^2)/2

Figure: http://session.masteringphysics.com/problemAsset/1037926/4/YF-10-44.jpg

Thank you in advance!

2007-12-09 11:42:59 · 3 answers · asked by pestuce 2

........., does 2 newton then means that you move a body of a mass of 2 kg in 2 seconds to a speed of 2meters/sec.?

2007-12-09 11:41:37 · 3 answers · asked by Anonymous

A bullet of mass 150 grams is fired into a block of mass 4kg with a velocity of 200m/s. The bullet penetrates the wood and stops. What is the speed of the system in m/s just after the bullet stops?

2007-12-09 11:27:04 · 3 answers · asked by Anonymous

An object weighing 300 N in air is immersed in water after being tied to a string connected to a balance. The scale now reads 265 N. Immersed in oil, the object appears to weigh 275 N. Find (a) the density of the object and (b) the density of the oil.

I am unsure of how to proceed with this problem. This is non-calculus based physics so fluidic resistance and mass of the string are negligible. A full solution would be great but the first few steps to how to do it would suffice. And before anyone starts thinking "Oh great another kid who cant do his own work", I am a student taking this physics as an elective. My major is business management and I am doing this because I enjoy it. Thanks a lot for the help!

2007-12-09 10:55:15 · 3 answers · asked by Anonymous

2007-12-09 10:44:49 · 10 answers · asked by Anonymous

I understand why we see (the light bouncing off object and back to our eyes). But as this light defines the shapes of objects. What tells us what colour these are. And why can't colour blind people and and animals see the same?

2007-12-09 09:48:52 · 4 answers · asked by exkillonator 2

t/f. a colorful pattern appears when a mica sheet is placed between polaroid sheets caused by the interference of double refracted light beams through the mica sheet.

2007-12-09 09:46:40 · 1 answers · asked by Anonymous

And if so, does it point towards the earth or towards the sun?

2007-12-09 09:42:27 · 3 answers · asked by Roy Nicolas 5

Hey I'm really confused! Please help, I have no idea where to start in even working this out!

A particle A of mass m travelling with a velocity v0 collides with a stationary particle B of mass 4m. After the collision, A travels at right angles to its original direction with speed v1 and B moves with speed v2at an angle of 60° to the original direction of A.

Show that after the collision v2 = [v0/(2sqrt3)] and find an expression for v1

Write down expressions for the total kinetic energies before and after the collision in terms of m and v0. Hence show that the ratio of final to initial kinetic energies is 2/3

Is the collision elastic or inelastic? Explain your answer.

2007-12-09 09:36:00 · 2 answers · asked by Hayley* 3

Ok if the definition of an AMU is 1/2 of the mass of a C-12 atom, then why aren't all nuclear masses round even decimals? This shows that no two protons and neutrons are the same size does it not? If they are the same masses, then what accounts for all the decimal parts of the atomic masses? Look on any table that gives nuclear masses in amu's. C-12 has a mass of 12.000000 but that is the only round one. Why?

2007-12-09 09:35:03 · 3 answers · asked by Anonymous

Also add the parts so i know what to buy, and also show the steps to make it.

2007-12-09 09:31:22 · 2 answers · asked by Bob S 1

If we cant see the fourth dimension of objects because of reduction caused by projection into the third dimension, does that have anything to do with why you cant see the light of a lazer until it is projected onto an object in our 3 d world?

2007-12-09 09:14:50 · 4 answers · asked by Johnny Tostado 2

A physics homework question :)
Uranus has a radius of 2.33e7m and is 2.87e12m from the sun. The sun has a radius of 6.96e8.

2007-12-09 09:09:18 · 1 answers · asked by Anonymous

The instantaneous rate of change for a sive wave like:
a sin (bx + k) is ab cos (bx + k)
The instantaneous rate of change for a cosine wave like:
a cos (bx + k) is -ab sin (bx + k).

So here's my question. that is only the rate of change for the function. BUT!!! For an energy wave, what is the rate of change for the speed of an energy wave? Is it the absolute value of the derivative?

2007-12-09 09:05:22 · 5 answers · asked by UnknownD 6

Two carts with masses of 4.60 kg and 3.04 kg move toward each other on a frictionless track with speeds of 5.37 m/s and 3.35 m/s respectively. The carts stick together after colliding head-on. Find the final speed.

2007-12-09 08:42:17 · 1 answers · asked by Anonymous

A 718 N student stands in the middle of a frozen pond having a radius of 4.7 m. He is unable to get to the other side because of a lack of friction between his shoes and the ice. To overcome this difficulty, he throws his 2.8 kg physics textbook horizontally toward the north shore at a speed of 5.5 m/s. How long does it take him to reach the south shore?

2007-12-09 08:35:35 · 2 answers · asked by Anonymous

1)what is the weight of a box that exerts a parallel force component of 330 N
and a perpendicular component of 390 N?

2)a net force of 15 N is applied to a cart with a mass of 2.1 kg
a) what is the acceleration of the cart?
b) how long will it take the cart to travel 2.8 m starting from rest?

3)a baseball is hit staright up into the air with a speed of 33 m/s.
a) how high does it go?
b) how long is it in the air?

please show how you did it if you can

2007-12-09 08:34:17 · 1 answers · asked by jolie. 1

What acceleration would a 175 kg box have on this ramp?
Can you please show me HOW you got the answer too?
THANK YOU in Advance!!

2007-12-09 08:27:21 · 2 answers · asked by Anonymous

A child on a 5.00 m long swing has a speed of 4.00 m/s at the bottom of the swing. What angle will the swing make with the vertical when the child reaches his highest point in the swing?

I think that the child has no potential energy in the beginning and has no kinetic energy at the end, but i dont know what to do then.

2007-12-09 08:20:28 · 1 answers · asked by Anonymous

2007-12-09 08:17:06 · 6 answers · asked by nighttime_ran 4

2007-12-09 08:08:39 · 3 answers · asked by Anonymous

And how is momentum involved?

2007-12-09 07:44:38 · 10 answers · asked by Anonymous

At time t=0 a grinding wheel has an angular velocity of 26.0 rad/s. It has a constant angular acceleration of 34.0 rad/s^2 until a circuit breaker trips at time t = 2.30 s. From then on, the wheel turns through an angle of 432 rad as it coasts to a stop at constant angular deceleration

a)Through what total angle did the wheel turn between t=0 and the time it stopped?
Express your answer in radians.

b)At what time does the wheel stop?
Express your answer in seconds.


c)What was the wheel's angular acceleration as it slowed down?
Express your answer in radians per second per second.

2007-12-09 06:41:33 · 1 answers · asked by cglrtk 1

2007-12-09 06:34:28 · 18 answers · asked by Anonymous

The bird perched on the swing shown below has a mass of 40.9 g, and the base of the swing, y = 7.87 cm below the hook, has a mass of 155 g. The swing and bird are originally at rest, and then the bird takes off horizontally at 2.02 m/s. How high will the base of the swing rise above its original level? Disregard friction.

2007-12-09 06:19:38 · 3 answers · asked by andyjumpman23 3

1.) can work be negative? (i.e. if you go up 1 flight of stairs (10m) and then go back done net work is 0?)
2.) If the work done on an object doubles its kinetic energy, does it double its velocity? If not, by what ratio does it change the velocity?- is the answer 1/4?

2007-12-09 06:11:39 · 2 answers · asked by Work Hard, Make Money, Enjoy Life... 3

Bicyclist has a tangential speed of 13.5m/s. Radius is 48.9 m. magnitude of force maintaing motion is 380 N. What is combined mass? Help please

2007-12-09 06:07:42 · 2 answers · asked by allda_jedi8472 1

Two lasers each produce 6.00 mW beams. The beam of laser B is wider, having twice the cross-sectional area as the beam of laser A.

Which of the following statements about these two laser beams is correct? (THERE MAY BE MORE THAN ONE CORRECT CHOICE.)
A. Both of the beams have the same average power.
B. Beam A has twice the intensity of beam B.
C. Beam B has twice the intensity of beam A.
D. Both beams have the same intensity.

2007-12-09 06:03:46 · 2 answers · asked by ~Brigit~ 2

A 974 N crate is pushed across level floor with 318 N at an angle of 23 degrees above the horizontal. kinetic friction is .25. acc. of gravity is 9.81. What is the acceleration of the box? I'm blank

2007-12-09 05:57:29 · 1 answers · asked by allda_jedi8472 1

2007-12-09 05:56:18 · 1 answers · asked by Anonymous