Physics - December 2007

On Answers I saw a couple answers refer to www.cleanmotorpower.com. This looks like a new power source. Would something that uses no fuel and no pollution, would that be ion or atomic? Has anyone else seen the website and what do you think of it?

2007-12-02 13:37:49 · 3 answers · asked by Anonymous

A source of light's 2m below the surface of a body of water.

2007-12-02 13:34:06 · 1 answers · asked by VanDaMan 1

A Coconut falls from the top of a tree and raches a velocity of 19.6 m/s when it hits the ground. It takes 2 seconds to reach the ground. What is the coconuts acceleration?

[[ Please help me with this. I do not understand it. Please show step by step how to get the answer, and what to write. Thank You ]]

2007-12-02 13:21:46 · 8 answers · asked by Anonymous

A ditch 2.5 m wide crosses a trail bike path. An upward incline of 15 (degrees) has been built up on the approach so that the top of the incline is level with the top of the ditch. What is the minimum speed at which a trail bike must be moving to clear the ditch? (Add 1.4 m to the range for the back of the bike to clear the ditch safely.)
I don't need the answer, just the work.

2007-12-02 13:21:37 · 1 answers · asked by Anonymous

A 3.10 kg block is pushed along the ceiling with an constant applied force of F = 86.5 N that acts at an angle = 52° with the horizontal, as in the figure below. The block accelerates to the right at 6.02 m/s2. Determine the coefficient of kinetic friction between the block and the ceiling.

and

A clerk moves a box of cans down an aisle by pulling on a strap attached to the box. The clerk pulls with a force of 184.0 N at an angle of 30° with the horizontal. The box has a mass of 31 kg, and the coefficient of kinetic friction between the box and the floor is 0.45. Find the acceleration of the box.v

2007-12-02 12:50:00 · 1 answers · asked by Anonymous

A clothesline is under tension when you hang from it. Why is the tension greater when the clothesline is strung horizontally than when it hangs vertically?

2007-12-02 12:44:34 · 1 answers · asked by Anonymous

When a certain metal is illuminated with light of frequency 3x1015 Hz, a stopping potential of 5.5 V is required to stop the ejected electrons. What is the work function of this metal in eV ?(Notice that the stopping potential is the potential difference required to bring the electrons with the maximum kinetic energy to a complete stop.)


The answer is in eV

please help me...................... =(

2007-12-02 12:26:28 · 1 answers · asked by Anonymous

anthony and sara are participating in the "Roll-a-Roma" rollerskating dance championship. While 75 kg Anthony rollerskates backwards at 3 m/s, 60 kg Sara jumps into his arms with a velocity of 5 m/s in the same direction

a). how fast does the pair roll backwards together?

b). If Anthony is skating toward sara when she jumps, would their combined final velocity be larger or smaller than your answer to part A?

2007-12-02 12:24:55 · 1 answers · asked by kiwi 1

A woman stands on a platform (with a frictionless pivot), which is rotating with an angular speed of 5.20 rad/s. Her arms are outstretched, and the rotational inertia of the platform+woman system is 5.4 kg·m2. She then pulls her arms in, so that now the system's rotational inertia is 4.20 kg·m2.

What will be her new angular speed when she pulls her arms in?


I'm not sure how to approach this problem, please help!

2007-12-02 11:53:40 · 2 answers · asked by =P 6

A clerk moves a box of cans down an aisle by pulling on a strap attached to the box. The clerk pulls with a force of 184.0 N at an angle of 30° with the horizontal. The box has a mass of 31 kg, and the coefficient of kinetic friction between the box and the floor is 0.45. Find the acceleration of the box.

AND

A 3.10 kg block is pushed along the ceiling with an constant applied force of F = 86.5 N that acts at an angle = 52° with the horizontal, as in the figure below. The block accelerates to the right at 6.02 m/s2. Determine the coefficient of kinetic friction between the block and the ceiling.

and

A 1.1 kg mass starts from rest and slides down an inclined plane 8.8 10-1 m long in 0.62 s. What net force is acting on the mass along the incline?

2007-12-02 11:53:10 · 1 answers · asked by Anonymous

Ice skaters use the conservation of angular momentum to produce high-speed spins when they bring their arms close to the rotation axis. Imagine a skater moves her arms inward, cutting the moment of inertia in half and therefore doubling the angular speed. If we consider the rotational kinetic energy, we see that the energy is doubled in this situation. Thus, angular momentum is conserved, but kinetic energy is not. Where does this extra energy come from?

2007-12-02 11:52:57 · 2 answers · asked by Mara F 2

A horiztonal force of 10 N is applied to a 1.0 kg block sitting on a flat surface. The coefficient of static friction between the block and the surface is 0.80, and the coefficient of kinetic friction is 0.70. Plot the velocity of the block as a function of time over the first five seconds. My question: how do you find the plot points?

2007-12-02 11:38:03 · 1 answers · asked by mathfan09 1

A block of mass m moving with a initial velocity V moves over a rough surface with a coeffcient of kinetic fricton u (mew). How long does it take for the block to come to a complete stop

A. V^2/2ug
B. V^2/2mug
C. V^2/ug
D. V/2ug
E. V/2mug

2007-12-02 11:14:45 · 1 answers · asked by Shot Caller 2

Its length increases by 8.35 x 10^-4 m. The rod is then cooled from 24.5°C to the freezing point of water. By how much does the rod shrink?


(please give whole problem workout) thanks in advance

2007-12-02 11:02:17 · 2 answers · asked by Anonymous

#1.Two long straight parallel wires separated by a distance of 20cm carry currents of 30A & 40A in opposite directions. What is the magnitude of the resulting magnetic field at a point 15cm from the wire carrying the 30A current & 25cm from the other wire?
#2.A point charge -Q is @ the center of a spherical conducting shell of inner radius R1 & outer radius R2. The charge on the inner surface of the shell is?
#3.If the current through a long solenoid is doubled while the coil's length is also doubled, keeping the total number of turns constant, the magnetic field at a point inside near the axis is?
#4.Two resistors are connected in parallel across a potential difference. The resistance of resistor A is twice that of resistor B. If the current carried by resistor A is I, then what is the current carried by B?
#5.Two identical bar magnets are dropped from equal heights. Magnet A is dropped from above the bare earth, whereas magnet B is dropped above a metal plate. Which will strike 1st?

2007-12-02 10:55:37 · 1 answers · asked by none 1

This is a Physics concept question and I have no idea.

2007-12-02 10:32:30 · 2 answers · asked by JQ 9 2

An 18 kg box is released on a 37 degree incline and accelerates down the incline at 0.270 m/s^2. Find the friction force impeding its motion. How large is the coefficient of friction?

Please show and explain all work please.

2007-12-02 10:21:18 · 1 answers · asked by Kantilal P 1

HOW DOES THE PHYSICS INVOLVES TO THE ROCKING CRITTER/HORSE??
IT'S FOR MY PHYSICS RESEARCH~
AND WHERE CAN I FIND IT??

2007-12-02 10:20:48 · 1 answers · asked by Anonymous

A) A force of 40N is required to pull a 10kg wooden block at a constant velocity across a smooth glass surface on Earth. what would be required to pull the same wooden block on the planet Jupiter???
Ok first off, it doesnt give the gravity due to accel on Jupiter, and i dont know any formulas. I drew it out and I'm just completely lost.. I looked up Jupiters actual gravity (24.5m/s^2) and used f=mg to find 245N. and then i set up a proportion, you know how 98 over 40 = 245 over x. that got me close to the answer but how do you actually find it the right way?

B) Use G(m1)(m2) over d^2 (newtons version of keplers 3rd law) to find the mass of the earth. the moon is 3.9e8m away from the earth and the moons period is 27.33 days. okay i dont have the mass of the moon and what does all of that have to do with the formula they told me??

C) the asteroid ceres has a mass of 7e20 kg and a radius of 500km. whats g on the surface? what formula do i use!? none of them help me with it!

2007-12-02 09:07:28 · 1 answers · asked by E 2

2007-12-02 08:57:25 · 14 answers · asked by Anonymous

An organ pipe that is open at both ends has a fundamental frequency of 389 Hz at 0°C. Using the fundamental frequency for this pipe at 20°C, what is the length of the organ pipe?

2007-12-02 08:52:58 · 1 answers · asked by Anonymous

A 62.0 kg person jumps from rest off a 10.0 m high tower straight down into the water. Neglect air resistance during the descent. She comes to rest 3.00 m under the surface of the water. Determine the magnitude of the average force that the water exerts on the diver. This force is nonconservative.

2007-12-02 08:49:41 · 2 answers · asked by scarlet123 2

A frictionless block of mass 1.95 kg is attached to an ideal spring with force constant 310 N/m. At t=0 the spring is neither stretched nor compressed and the block is moving in the negative direction at a speed of 12.6 m/s.

Find the amplitude.

Find the phase angle.

2007-12-02 08:48:14 · 3 answers · asked by Bugz 3

A 35 g ball released from rest falls vertically. It hits the ground and remains in contact with it for .5 ms. Rebounding elastically, it returns to its original height. The whole trip takes 8 s. Calculate the average force on the ball during contact with the ground.

2007-12-02 08:46:26 · 3 answers · asked by Anonymous

An astronaut in full space gear climbs a vertical ladder on the earth. The astronaut then makes the same climb on the moon. In which location does the gravatational potential energy of the astronaut change more? Why?

2007-12-02 08:44:35 · 1 answers · asked by Rosy 2

If the Doplar shift indicated that the shift was to blue violet on the spectrum would the big bang explain the theory?

2007-12-02 08:38:07 · 8 answers · asked by Anonymous

2007-12-02 08:32:05 · 2 answers · asked by J L 2

Heres a few conceptual questions. i would greatly appreciate any knowledge or thinking. you dont have to answer all of them. i know i cant



1) A spaceship that is spherical in shape travels past an observer who is stationary on earth. Assume that the spaceship has a velocity of 0.8c and travels in a straight line. What shape will the observer see as the spaceship travels past? Explain your answer.


2) Consider the spaceship above. What observation will the earth observer make of the density of the spaceship? Explain your answer.


3) Consider the statement matter can be neither created nor destroyed. In view of your knowledge of Special Relativity is this statement correct? If not how would you correct it.


4) Consider the statement: a compressed spring has more mass than the same spring that isn’t compressed. Explain this.

2007-12-02 08:31:35 · 2 answers · asked by Anonymous

2007-12-02 08:29:38 · 3 answers · asked by Anonymous

Is it wrong of me to make an argument stating Perpetual Motion is possible? That some day, we WILL have free energy, by some means that cant be controlled by the time of day, weather, or if the river is flowing (Solar, Wind, and Hydo- power)? Are magnets the answer? Look at Stem Cell research, how long ago did that come about, and every said it wouldn't work, or that THAT was impossible? Look at how far cars have come due to new technology. Look how far computers have come, they have basically taken over our world.

Would it be possible to make a machine, that once you give it a little start, it could produce enough energy to keep itself going, and spare some in the form of say electricity? or make enough power to move a car or truck?

I'm just looking for anything I can use to make my future studies teacher believe my "Future car" could be self powered some how. I have been reading on Perpetual motion for a while now, and believe it will someday be our savior lol

2007-12-02 08:21:55 · 9 answers · asked by louie 2