Physics - November 2006

2006-11-03 14:15:50 · 9 answers · asked by generalche22 3

We can use the textbook results for head-on elastic collisions to analyze the recoil of the Earth when a ball bounces off a wall embedded in the Earth. Suppose a professional baseball pitcher hurls a baseball (m = 155 grams = 0.155 kg) with a speed of 98 miles per hour (vball = 43.1 m/s) at a wall, and the ball bounces back with little loss of kinetic energy.

(a) What is the recoil speed of the Earth (M = 61024 kg)?


(b) Calculate the recoil kinetic energy of the Earth and compare to the kinetic energy of the baseball. The Earth gets lots of momentum (twice the momentum of the baseball) but very little kinetic energy.


I think i could figure this out if I knew how to write up the energy principle equation. Either way, can someone please explain how to do this? I just wanna get this done (but also how i can do it of course)

Thanks everyone

2006-11-03 14:15:14 · 2 answers · asked by jnieves01 1

Little boy was a 12 killaton bomb. Could they make one with only a few hundred pounds of TNT yield?

2006-11-03 14:08:03 · 3 answers · asked by Anonymous

A phone cal froom city x to city y costs $1.00 for the first 3 min and $0.20 for each addtional minute. If r is an integer greater than 3m a phone call r minutes long will cost how many dollars?

r+2/5 is answer

3*10^4 is greater than 4*103 by wht percent

among the 2 which is greater
1>the volume of a can that is right circular cylinder wtih radius of 5 centimeters

2>the volume of a can that is right circular cylinder wtih radius of 4 centimeters


Of 65 people polled , 20% said that, givner the choice among thr 3 colors red, blue, and green they preferred the color blue.
1>the number of people who said they prefered the color blue?
2>one-half the number of people who said they prefered the color green?


pls answer to all these questions

2006-11-03 14:02:25 · 1 answers · asked by lak p 1

A garden hose of inner diameter 2 cm carries water at 2 m/s. The nozzle at the end has diameter 0.42 cm. How fast does the water move through the nozzle?

2006-11-03 13:55:27 · 5 answers · asked by Anonymous

It is supposed to be a uniform angle, not dependant on mass, weight, velocity etc. The mass starts at the top of the circular object and begins sliding down the circle eventually there is a point when it gets airborne. Anyone know?? I have tried searching and can't find answer! Thanks

2006-11-03 13:54:06 · 5 answers · asked by Anonymous

a) if the rate of motion changes so that the magnet is plunged in andn out 6 times per second, what will the be the new induced voltage?
b) if the number odf coils in the wire is doubled from 100 to 200, and the original rate of 2 times per second is kept the same, what will be the new voltage induced?

2006-11-03 13:33:59 · 2 answers · asked by Anonymous

A baton twirler throws a spinning baton directly upward. As it goes up and returns to the twirler's hand, the baton turns through five revolutions. Ignoring air resistance and assuming that the average angular speed of the baton is 1.70 rev/s, determine the height to which the center of the baton travels above the point of release.

in meters.

Okay. How do I figure out the distance from angular kinematic equations? What equations would I use? (Yes, I feel kind of stupid because this seems like a simple question, but I can't figure it out).

2006-11-03 13:29:45 · 2 answers · asked by Confused 1

1) A clerk moves a box of cans down an aisle by pulling on a rope attached to the box. The clerk pulls with a force of 188 N at an angle of 25.0° with the horizontal. The box has a mass of 36.9 kg, and the coefficient of kinetic friction between box and floor is 0.450. Find the acceleration of the box.

2)A box of books weighing 259 N is shoved across the floor by a force of 435 N exerted downward at an angle of 35° below the horizontal.

(a) If µk between the box and the floor is 0.57, how long does it take to move the box 9 m, starting from rest? (If the box will not move, enter 0.)

(b) If µk between the box and the floor is 0.75, how long does it take to move the box 7 m, starting from rest? (If the box will not move, enter 0.)

--what do the symbols even mean.... so yeah im really lost if u guys could explain how to do these probs so i know in the future, i'd appreciate it a lot. thanks

2006-11-03 13:00:35 · 3 answers · asked by Anonymous

A baseball outfielder throws a baseball of mass 0.15 kg at a speed of 40 m/s and initial angle of 30 degree with horizontal. What is the kinetic energy of the baseball at the highest point of the trajectory? Ignore air friction

2006-11-03 12:33:46 · 7 answers · asked by mastersource2005 5

Why can't we use it for levitation and motion? I've heard of maglev trains but that requires a track. Is it physically impossible? If so, why?

2006-11-03 11:23:40 · 8 answers · asked by timespiral 4

2006-11-03 11:16:07 · 8 answers · asked by Budz 69 1

Say I have two sine waves, one of 500hz and another of 510hz, both with an initial phase of 0 degrees. What is the relationship, if any, of the two signals' phase difference over time as caused by the frequency difference?

2006-11-03 10:34:41 · 2 answers · asked by jerkables 1

question a:
How high will a 0.350 kg rock go if thrown straight up by someone who does 118 J of work on it? Neglect air resistance.
______m


question b:
A 305 kg piano slides 4.2 m down a 30° incline and is kept from accelerating by a man who is pushing back on it parallel to the incline. The effective coefficient of kinetic friction is 0.40.
1)Calculate the force exerted by the man.
______N
2)Calculate the work done by the man on the piano.
______J
3)Calculate the work done by the friction force.
______J
4)What is the work done by the force of gravity?
______ J
5)What is the net work done on the piano?
______J


question c:
A spring has k = 88 N/m. Use a graph to determine the work needed to stretch it from x = 3.8 cm to x = 4.8 cm, where x is the displacement from its unstretched length.
______J

2006-11-03 10:01:02 · 9 answers · asked by tigerlilly 2

problem 1:
A ball on the end of a string is cleverly revolved at a uniform rate in a vertical circle of radius 75.0 cm. Its speed is 4.00 m/s and its mass is 0.300 kg.

(a) Calculate the tension in the string when the ball is at the top of its path.
________ N
(b) Calculate the tension in the string when the ball is at the bottom of its path.
_______N



problem 2:
A 970 N crate rests on the floor.
(a) How much work is required to move it at constant speed 6.7 m along the floor against a friction force of 180 N?
________ J
(b) How much work is required to move it at constant speed 6.7 m vertically?
________J

2006-11-03 09:55:54 · 4 answers · asked by tigerlilly 2

GCSE level ansers

2006-11-03 09:47:30 · 4 answers · asked by sabrina 3

Fluid pressure??? I need to solve this problem:
The scuba diver went 15 m deep. what is the fluid pressure?

2006-11-03 09:20:29 · 5 answers · asked by Anonymous

Why an A-bomb makes a mushroom-shaped cloud after the explosion? There should be a cloud surely but why in such shape? (In your answer, technical details can be used since I am well informed with the terminology of the subject.) Thank you.

2006-11-03 09:00:11 · 10 answers · asked by Fatih 1

Premise belive read one rational given by Albert Einsteine why he founded General Theory of Relalativity was to explain disparity in completely accepted speed of light and some astronical observations.
Question has astromical snapshot of speed of light ever been measured passing known planets full of green vegation?
Wild spelation: Could green vegation through some unknown attraction slow speed of light in deep space. Comment if you'd like to.

2006-11-03 08:50:19 · 7 answers · asked by Mister2-15-2 7

Best answer gets a nobel prize in physics and 10 points.

2006-11-03 08:44:15 · 14 answers · asked by maddogs ghost 1

or at least whose the first one discover it or find out about it?

2006-11-03 08:26:53 · 3 answers · asked by Anonymous

I understand glue factories used ti use them. Where else are they used, or who makes them in Britain?

2006-11-03 08:12:41 · 5 answers · asked by pauldbrownlie 2

I recently read somewhere that mathematicians are unable to define or prove randomness. and although some sequences of numbers are categorized as random, these are only educated guesses...Please enlighten.

2006-11-03 08:10:20 · 4 answers · asked by Anwar Ali 2

if we had an antimatter generating station orbiting the sun or something and it didn't cost billions of dollars for a microgram...

could small pieces of antimatter be held inside a permanent magnet sphere (in a vacuum obviously), and then a simple timing device that would release a pin and crack the sphere thus causing an explosion.

are the physics behind that possible and could that method be used to make small grenades and bombs of great power?

2006-11-03 07:49:04 · 3 answers · asked by Anonymous

A dike is holding back the sea from a town below sea level and it springs a leak 3.1m below the water surface. If the area of the hole in the dike is 0.012m^2, what force is needed to save the town? (The density of the sea water is 1025kg/m^3)

2006-11-03 07:48:59 · 3 answers · asked by brilliantdance12 1

A freight train has a mass of 1.6 107 kg. If the locomotive can exert a constant pull of 8.5 105 N, how long does it take to increase the speed of the train from rest to 70 km/h?

2006-11-03 07:28:09 · 3 answers · asked by Tennis2127 2

2006-11-03 07:17:14 · 13 answers · asked by thiskidthattheylove 2

A high tech jet car speeds along the desert floor at a constant velocity of 180 miles/hr north.a) what is the net force on the jet car?
the jet car hits some sand which causes a drag force on the car of 5000 N to the south. The computer instantly compensates so the jet exerts a thrust force on the car of exactly 5000 N to the north at the same time the car hits the sand. The jet car now... choose ALL that apply:
slows down
remains at rest
maintains constant velocity
moves with constant non-zero velocity
speeds up
moves with a changing velocity
accelerates at a constant rate

Newton's first law states: When the ____ on an object is zero, the object will ____ constant ____.
Another way of saying this is that, if the total force on it equals zero, an object's ___ will also be zero.

Is it necessary to apply a force to keep an object going in a circle at constant speed?
Yes/No, because the ____ is changing/not changing.

2006-11-03 07:13:33 · 2 answers · asked by vintagex50s 2

An obect in motion keeps going because it has ______ (one word answer).

Inertia is/is not a force.

inertia would be best described as... (CHOOSE ALL THAT APPLY)
mass
resistance to change in velocity
the tendency to maintain constant velocity
the force of gravity
resistance to acceleration
a force within the object
a property of matter

A piece of cheese is at rest. A gerbil pulls to the left with 1.5 N at the same time as a mouse pulls to the right with 1.5 N.
what is the net force on the piece of cheese?
What does the cheese do in this situation? choose ALL that apply:
moves with constant non-zero velocity
accelerates at a constant rate
remains at rest
maintains constant velocity
speeds up
moves with a changing velocity
slows down

2006-11-03 07:10:41 · 4 answers · asked by vintagex50s 2

2006-11-03 07:05:01 · 19 answers · asked by Brian G 1