Physics - November 2007

2007-11-26 16:13:59 · 2 answers · asked by georgie0515 1

1) What is the frequency, in hertz, that corresponds to each of the following periods?
a) 0.10s? __Hz
b) 4s? __Hz
c) 1/40s? __Hz

2)A skipper on a boat notices wave crests passing his anchor chain every 5 s. He estimates the distance between wave crests to be 15 m. He also correctly estimates the speed of the waves. What is this speed? __m/s

3)A mosquito flaps its wings 640 vibrations per second, which produces the annoying 640 Hz buzz. The speed of sound is 340 m/s. How far does the sound travel between wing beats? In other words, find the wavelength of the mosquito's sound. ____m

4)What is the period, in seconds, that corresponds to each of the following frequencies?
a) 9Hz ___s
b) 0.30Hz ___s
c) 60Hz ___s

5)Radio waves travel at the speed of light: 300000 km/s. What is the wavelength of radio waves received at 700 MHz on your radio dial? ___m

2007-11-26 16:03:52 · 2 answers · asked by TheLostOne 3

The approximate volume of the granite monolith known as El Capitan in Yosemite National Park is about 10^8 m^3. What is its approximate mass?

2007-11-26 15:51:55 · 5 answers · asked by Callie 1

When an automobile moves with constant velocity, the power developed is used to overcome the frictional forces exerted by the air and the road. If the engine develops 30 hp, what total frictional force acts on the car at 120 mph?


1hp = 746W
1mile-1609m
work=force*distance
power= work/time

30hp= 22380w
120mph= 53.6448m/s
I'm really not sure where to go from there, you need to end up with force which is Newtons, dont you need a mass in kg to for that?

2007-11-26 15:30:32 · 2 answers · asked by Katie E 2

What is the difference between a permanent magnet and an electromagnet?
What is the relationship between the direction of magnetic field generated and the electric field?
How can you increase the magnetic field generated?

2007-11-26 15:26:32 · 5 answers · asked by Anonymous

Of the five places listed below it would be easiest to launch a spacecraft from the earth from:

a) New Mexico (south over Mexico)
b) California (north over the Pacific Ocean)
c) Florida (east over the Atlantic Ocean)
d) Moscow (east over Siberia)

The first trip to the moon was, in fact, launched from (see above):

a) b) c) d) e)

A century ago Jules Verne thought the journey to the moon would commence from:

a) b) c) d) e)

2007-11-26 15:24:29 · 1 answers · asked by ? 6

12-6) Your doctor's scale uses a slidable weight on an arm to balance your weight. These weights are obviously much lighter than you are. How does this work?

Please help, thanks!

2007-11-26 15:17:49 · 3 answers · asked by Kiwikahuna 2

Place three wooden dowels with different diameters on lumps of clay. Put a heavy book on top of each dowel. Which dowel sinks deepest into the clay, the one with largest diameter or the one with smallest diameter? Please explain it.
Thanks!

2007-11-26 15:14:43 · 3 answers · asked by Anonymous

2007-11-26 14:17:28 · 6 answers · asked by Ace of Spades 5

what are the ways of increasing and decreasing friction

2007-11-26 14:14:46 · 4 answers · asked by giselle 1

Two motorboats on opposite shores of a river start moving towards eachother, but at different speeds. Please neglect all other factors like acceleration , turn-around time, and current. When the two boats pass one another the first time, they are 700 meters from one shoreline. Each continues to the opposite shores, then turns around and begins moving towards one another again. When they pass the second time, they are 300 meters from the other shoreline. (Their speeds, though different, remain constant). How wide is the river???

2007-11-26 13:57:39 · 1 answers · asked by Anonymous

The empire's space station is a long way from any star. It is circular and has a radius of 5 km. Calculate the angular velocity that is needed to give the station an artificial gravity of 9.80 m/s^2 at its circumference. If the space station is initially stationary and it is accelerated at rate of 8x10^-5 rad/s^2 , then how long does it take for the space station to reach this angular velocity? What angular displacement does it rotate through during this time?

2007-11-26 13:44:39 · 1 answers · asked by korr 2

a 0.50kg steel ball travelling at 20m/s strikes very large block and rebounds the same speed. the ball and block deform during the impact allowing the ball's center of mass to move only one tenth milimeter.
A) what is the acceleration of ball during the impact?
if you know this problem, please do it.
thank you

2007-11-26 13:37:37 · 2 answers · asked by alkesh831 2

A ball player hits a home run and the baseball just clears a wall 8.00 meters high located at 106.2 meters from home plate. The ball is hit at an angle of 36.1 degrees to the horizontal, and air resistance is negligible. Assume the ball is hit at a height of 1.1 meters about the ground. The acceleration of gravity is 9.81m/s/s
1. What is the initial speed of the ball? (m/s)
2. How much time does it take for the ball to reach the wall? (seconds)
3. Find the speed of the ball when it reaches the wall. (m/s)

2007-11-26 13:16:55 · 1 answers · asked by Anonymous

1. Which law was originally stated in terms of momentum?
2. Which law governs when to skaters push apart in a rink?
3. Which law governs the max. efficiency of a refrigerator?

2007-11-26 13:13:45 · 8 answers · asked by Anonymous

A heat engine absorbs 1704 J from a hot reservoir and expels 1196 J to a cold reservoir in each cycle.
(a) What is the engine's efficiency?
______%
(b) How much work is done in each cycle?
______J
(c) What is the power output of the engine if each cycle lasts for 0.299 s?
_____W

2007-11-26 13:06:24 · 2 answers · asked by Anonymous

2007-11-26 13:05:07 · 4 answers · asked by lope star 1

2007-11-26 13:00:22 · 4 answers · asked by skooteric 1

Well, my teacher assigned us homework and I've been gone for 2 weeks sick + Thanksgiving break, and I really have no idea what I'm doing. My grade right now in there is terrible, and it's dragging my GPA down a ton. It's basically a chart:

Angles | 15 | 30 | 45 | 60 | 75 | 90 | 5 | 85 |
______
Velocity | 200 | 200 | 200 | 200 | 200 | 200 | 200 | 200 |
______

V ox
_______

V oy

_______

T hang

_______

X max

_______

Y max

_______


Normally I wouldn't ask for something like this here, but my teacher is going to slaughter me if I don't get this done. I'm completley stumped and have been sitting in front of a blank piece of paper for a half an hour.

If you can't solve them, could someone at least try and explain what this is to me?

2007-11-26 12:59:20 · 2 answers · asked by Anonymous

A 2.0 kg otter starts from the rest at the top of a muddy incline 85 cm long and slides down to the bottom in 0.50 seconds. What net external force acts on the otter along the inline?? How do find the answer??

PLEASE HELP!!!!! THANKS IN ADVANCE TO THOSE WHO DO!!!

2007-11-26 12:59:09 · 1 answers · asked by Anonymous

2007-11-26 12:51:53 · 3 answers · asked by Khang 1

Steel sliding across steel has a  of .41. 50 N of steel is pushed with a force of 22 N. What would happen to the piece of steel – stay still, move at a constant velocity, or accelerate?

2007-11-26 12:49:36 · 2 answers · asked by Anonymous

A baseball (m = 145 g) traveling 30 m/s moves a fielder's glove backward 35 cm when the ball is caught. What was the average force exerted by the ball on the glove?
Magnitude
______N

2007-11-26 12:47:38 · 4 answers · asked by lcbby 1

The earth's radius is 6400 km. A 25 kg mass is taken 201 km above the earth's surface. What is the weight of the object at this height? please show work...im really lost -_-

2007-11-26 12:45:31 · 1 answers · asked by cowluver 3

1. Why do you think scientists have only recently discovered subatomic particles?
2. What might scientists learn by breaking apart an atomic nuclei?

2007-11-26 12:44:46 · 2 answers · asked by Anonymous

Two ropes pull on a ring. One exerts a 47 N force at 30.0°, the other a 47 N force at 60.0°
(a) What is the net force on the ring?
Magnitude
____ N
Direction
____ °
(b) What are the magnitude and direction of the force that would cause the ring to be in equilibrium?
____ N
____ °

2007-11-26 12:44:38 · 3 answers · asked by Anonymous

do you know what is nuclear power plants? can you please type in easy sentences, because my english is not quit good!!!!!! so please help me out!!!!!!

another question are...............
is nuclear power plats use oil for.........?
when there will be run out of oil?
pls pls

2007-11-26 12:44:29 · 2 answers · asked by a2yeasmin 1

I need to build a toothpick bridge for physics. Which should I use?

2007-11-26 12:38:55 · 1 answers · asked by lehdownthebeat3 1

This is a webassign question. I did all the rest but can't figure this one out.
Here it goes:
A student stands on a bathroom scale in an elevator at rest on the 64th floor of a building. The scale reads 847 N.

(a) As the elevator moves up, the scale reading increases to 952 N, then decreases back to 847 N. Find the acceleration of the elevator (m/s/s).

(b) As the elevator approaches the 74th floor, the scale reading drops to 782 N. What is the acceleration of the elevator?
m/s2
(c) Using your results from parts a and b, explain which change in velocity, starting or stopping, would take the longer time.
stopping
starting

(d) What changes would you expect in the scale readings on the ride back down?

2007-11-26 12:38:23 · 2 answers · asked by Iris S 2

This is not a homework question. i am merely posting this on here in hopes that you guys can settle a bet between a friend of mine.

2007-11-26 12:35:23 · 1 answers · asked by KEVIN 3