Physics - September 2007

this has something to be with physics. the frequencies may seem to be higher as it approaches a boil.. i want to know what exactly happens in the kettle.

2007-09-29 16:53:56 · 2 answers · asked by lipids 1

Is it possible that in the experiments done to test time dilation, there was only a physical effect on the atomic clocks that made it seem like the actual "time"has changed? Could it be the "relativistiv mass increase thing, or somehow the atoms in the clock were slowed down, but not due to time change?

2007-09-29 16:28:21 · 5 answers · asked by Michael n 2

In 1947 Bob Feller, a pitcher for the Cleveland Indians, threw a baseball across the plate at 98.6 mph or 44.1 m/s. For many years this was the fastest pitch ever measured. If Bob had thrown the pitch straight up up, how high would it have gone? Please tell me how to solve this!

2007-09-29 16:06:16 · 2 answers · asked by James J 1

So I've been stuck on this problem for some time. It seems my physics class will be the end of me. Please help me understand this problem.
A stone falls FROM REST off a cliff and then a second stone is thrown with initial speed of 74.48 m/s after 3.8 secs the first one. Acc due to grav is 9.8. both hit the ground at the same time. (HOW IS THIS POSSIBLE!!!) so the q asks that how long does the first stone take to hit the ground and how high the cliff is?
Please help me!

2007-09-29 16:05:20 · 5 answers · asked by Crashovdr 4

1. Explain why a motorcycle is tilted as it rounds a curve.
2. Explain why a clothesline with a wet towel hung at the center of the line cannot remain stretched taut between two poles.
3. The mass of the moon is about 1% that of the earth. Is the centripetal force that keeps the moon in its orbit around the earth much smaller than, the same as, or much greater than the gravitational force exerted on the moon by the earth?
4. Give one example in which the distance traveled is a significant amount yet the corresponding displacement is zero.
5. Give one example of a physical system where a particle moves at constant velocity while at the same time has acceleration.
6. Explain the difference of a conservative and a non-conservative force and give one example of each.
7. When you climb a mountain, is the work done on you by gravity different if you take a short, steep trail instead of a long, gentle trail? If not, why do you find one trail easier?

2007-09-29 15:32:11 · 2 answers · asked by la 1

my goal is to get 90%
but i havent started well
i got 6 /10 on the quiz
68% on the unit test
and 14/15 for the experiment
please help me improve

2007-09-29 15:29:28 · 2 answers · asked by king of soccer 1

A pebble is dropped in a lake and it produces ripples with a frequency of 0.25Hz. When should a second pebble be dropped at the same place to produce destuctive interference?

a. 0.50 s after the first
b. 0.75 s after the first
c. 1.0 s after the first
d. 1.5 s after the first
e. 2.0 s after the first

Thanks :)

2007-09-29 15:21:51 · 1 answers · asked by Corian 2

i'm doing a lab report so one of the topics is to explain the formula to find density. I know it's a ratio, but i need for information besides that. Thank you!

2007-09-29 15:11:25 · 9 answers · asked by osomi_m 2

How long does it take the car to cover this distance? What equation should i use and how can i show my work? Thanks to all who answer!!!

2007-09-29 14:36:47 · 3 answers · asked by cooldude123 2

2007-09-29 14:08:35 · 21 answers · asked by nathan c 1

A jacks screw has Ideal Mechanical Advantage of 25lb, and a force of 40lb is applied to lift a load of 300lb. What load can be lifted by the machine if it is operated by a force of 60lb?

2007-09-29 14:03:04 · 1 answers · asked by Jay 1

A chain hoist furnished with 120 hp lifts to a height of 40 ft in 20 sec.

2007-09-29 13:50:37 · 2 answers · asked by Jay 1

I'm doing a practice exam for our first Calc 1 test, and question 7 part b) asks: Find f'(x) of y=(x^5 + 4x^3 - x)^6. I know the formula for f'(x) is lim(h->0) [f(x+h)-f(x)]/h, and I can do this problem the traditional way but it would take FOREVER to take all of those x+h's to the different powers, then find the entire f(x+h) to the sixth power and f(x) to the sixth...

Given that this is just a part of one question.. and part a) was easy.. and the test has to be completed within an hour, there must be some exponential rules that allow this to be done much more quickly. Can anyone help?

2007-09-29 13:36:57 · 4 answers · asked by tcotier 1

two parallel plates 1.0 cm apart are equally and oppositely charged. An electron is released from rest at the surface of the negative plate and simultaneously a proton is released from rest at the surface of the positive plate. How far from the negative plate is the point at which the electron and proton pass each other?

2007-09-29 13:35:02 · 4 answers · asked by biscuits 2

A 50.5kg crate is at rest on a level floor and the coeffecient of kinetic friction is 0.384. The accleration of gravity is 9.8m/s2. If the crate is pushed horizontally with a force of 279.361 newtons, how far does it move in 2.69s. (in meters)

2007-09-29 12:35:22 · 1 answers · asked by Handiman 3

One strategy in a snowball fight is to throw a snowball at a high angle over level ground. Then, while your opponent is watching that snowball, you throw a second one at a low angle timed to arrive before or at the same time as the first one. Assume both snowballs are thrown at 25.0 m/s. The first is thrown at an angle of 70 degrees with respect to the horizontal.
a) At what angle should the 2nd snowball be thrown to arrive at the same point as the 1st?
b) How many seconds later should the second snowball be thrown after the 1st in order for both to arrive at the same time?

2007-09-29 12:28:26 · 1 answers · asked by boy101 3

traveling 130 km in 2.40 h.
What is his total displacement?

2007-09-29 12:23:51 · 2 answers · asked by Alan H 1

a perfect balance of both male and female. I love me!

2007-09-29 11:17:04 · 4 answers · asked by Treat 3

2007-09-29 10:40:17 · 5 answers · asked by The Walkin' Dude 4

2007-09-29 10:39:38 · 1 answers · asked by Anonymous

Explain your reasoning.

2007-09-29 09:35:59 · 8 answers · asked by lolabarry 2

2007-09-29 09:31:57 · 5 answers · asked by lolabarry 2

electromagnetic radiation with a wavelength of 531 nm appears as green light to the human light. The energy of one photon of this light is 3.14 x 10^ -19. thus, a laser that emits 1.3 x 10^ -2 J of energy in a pulse of light at this wavelength produces _________ photons in each pulse?



can someone please help me work this problem out?

a. 9.2 e(-24)
b. 3.5e (16)
C. 2.9 e(-17)
d. 1.8 e (19)
e. 6.5 e (13)

2007-09-29 09:23:17 · 3 answers · asked by Anonymous

2007-09-29 06:23:35 · 4 answers · asked by Anonymous

at each instant, can you compute the vehicle's position after a certain time from these data? If so, explain how this might be done.

2007-09-29 06:21:06 · 2 answers · asked by Anonymous

I have and experiment that i gotta do so how do i prevent a water ballon from popping when i drop it down several feet. any ideas for cushions or a parachute maybe?

2007-09-29 06:16:54 · 4 answers · asked by Anonymous

height. Is the magnitude of the acceleration greater while it is being thrown or after it leave your hand? Explain.

2007-09-29 06:12:35 · 2 answers · asked by Anonymous

Person throws .15 kg baseball at speed of 42 m/s. Initial angle is 20 degrees. What is KE of ball at highest point?

2007-09-29 06:08:09 · 1 answers · asked by ひいらぎ 5

hello i came across a question in my physics homework that i will really appreciate help with. Here it is:

at 3:00 p.m. a truck traveling on a winding highway has a velocity of 82.0 km/h [N 38.2 E] ; at 3:15 p.m., it has a velocity of 82.0 km/h [E 12.7 S]. Assuming that +x is easy and +y is north, determine the x- and y-components of the average acceleration during this time interval.

the answer at the back of the book:
a av,x = 9.0 x 10^-3 m/s^2
a av,y = -2.5 x 10^-2 m/s^2

thanks a lot for anyhelp!

2007-09-29 05:32:07 · 2 answers · asked by Anonymous

Does this sound right?:

A cable is pulling an elevator *upwards*,
The tension(T) in the cable would be:
T=m*a+9.8m/s^2

2007-09-29 04:56:08 · 2 answers · asked by RogerDodger 1