Physics - November 2007

2007-11-07 14:43:39 · 12 answers · asked by kiwi 1

A boat travels 24 m.p.h. in still water. It takes 5 hours to travel downstream & 7 hours to travel upstream. How fast is the water moving?

2007-11-07 14:42:25 · 2 answers · asked by malissa h 1

A 12250 N car traveling at 46.0 km/h rounds a curve of radius 2.00x10^2 m.

(a) Find the centripetal acceleration of the car.

(b) Find the force that maintains centripetal acceleration.

(c) Find the minimum coefficient of static friction between the tires and the road that will allow the car to round the curve safely

2007-11-07 14:38:56 · 2 answers · asked by Asdasd A 1

From the equation F = mv2/r, the tension in a 1 m length of string that whirls a 3 kg mass at 4 m/s in a horizontal circle is calculated to be 48 N. Calculate the tension for the following cases.


(a) twice the mass

(b) twice the speed

(c) twice the length of string (radial distance)

(d) twice mass, twice speed, and twice distance all at the same time

2007-11-07 14:34:58 · 1 answers · asked by Asdasd A 1

If the length of the tube is 4 meters, how many resonances would you observe when a tuning fork of frequency 256 Hz is used?

2007-11-07 14:33:29 · 2 answers · asked by Anonymous

2007-11-07 14:29:10 · 1 answers · asked by le sabre 4

A wheel spins in the counterclockwise direction.

(a) If its initial angular velocity was +7.13 rad/s and it rotated an angular displacement of +13.5 revolutions before coming to rest, what was its angular acceleration vector?

(b) How long did the wheel rotate?


Im confused on which equations to use to approach the problem, please help!

2007-11-07 14:24:55 · 2 answers · asked by =P 6

2007-11-07 13:59:26 · 6 answers · asked by Anonymous

I.E. using 3rd law of motion (4 every action there is an equal and opposite reaction.

What I need to know is how this is applied to a rollar coaster, more specifically marble one.

2007-11-07 13:43:18 · 13 answers · asked by ✔ 5

This is the entire question: A 9.0 g coin moving to the right at 25.0 cm/s makes an elastic head-on collision with a 19.0 g coin that is initially at rest. After the collision, the 9.0 g coin moves to the left at 12.5 cm/s.


Find the amount of kinetic energy transferred to the 19.0 g coin.

the final velocity is 17.76 cm/s to the right

Im trying to find the Kinetic energy transferred to the 19g or .019kg coin.
Please help me, i am a very confused asian boy.

2007-11-07 13:42:57 · 1 answers · asked by Troubled 3

As a simple pendulum swings back and forth, the forces acting on the suspended object are the force of gravity, the tension in the supporting cord, and air resistance.

2007-11-07 13:17:50 · 2 answers · asked by ? 1

2007-11-07 13:11:10 · 1 answers · asked by MIXAHL A 1

2007-11-07 13:08:44 · 10 answers · asked by Anonymous

First have wormsholes been proven impossible?

1)If we can use wormsholes for space exploration what will be needed to create one?

2)How much engery would be needed to create wormhole and keep it open?

3) How would we pass through it? Would we be torn into atoms?

4) Do we need a device at the other end of the wormhole to create a stable connection or do we just go around opening holes in space?

5) I'm not sure if wormholes punch holes in space and you magically appear at one end or bend space to two points for which travel can be made? Can someone please clarify this?

6) If wormholes bend space would not the matter between the space that was bend be destoryed?

Thanks for answering.

2007-11-07 12:56:40 · 3 answers · asked by jack 6

Someone was walking and they felt a vibration. A few seconds later they hear a loud explosion. What is the reason for this?

2007-11-07 12:51:47 · 1 answers · asked by jenn 4

Consider two mass, 3.2kg and 7.1kg, connected by a string passing over a pulley having a moment of inertia 11gm^2 about its axis of rotation. The string doesn't slip on the pulley, and the system is released from rest. The radius of the pulley is 0.33m.

Find the linear speed of the masses after the 7.1kg mass descends through a distance 33cm. Assume mechanical energy is conserved during the motion.

PLEASE PLEASE HELP!!!!

2007-11-07 12:28:20 · 1 answers · asked by Anonymous

I used to own a 5mw green laser and the beam could clearly be seen at night. What about a blue laser?

2007-11-07 12:24:58 · 14 answers · asked by techtonick.com 2

2007-11-07 12:15:58 · 8 answers · asked by Alla Z 1

2007-11-07 12:12:26 · 4 answers · asked by Shawn 1

Winter is approaching and everytime the temperature drops, I get more prone to being electrocuted from static buildup while driving my car. And when I say electrocuted, I really mean it. It's very itensive. Obviously, it has to do with my rubber soles, but how can I avoid getting shocked ? or What techniques do you use to avoid getting shocked when you notice the buildup of static ?

2007-11-07 12:09:58 · 2 answers · asked by SR 2

The string in a yo-yo is wound around an axle of radius 0.545 cm. The yo-yo has both rotational and translational motion, like a rolling object, and has mass 0.274 kg and outer radius 1.96 cm. Starting from rest, it rotates and falls a distance of 1.50 m (the length of the string). Assume for simplicity that the yo-yo is a uniform circular disk and that the string is thin compared to the radius of the axle.

(a) What is the speed of the yo-yo when it reaches the distance of 1.50 m?
_______m/s
(b) How long does it take to fall? [Hint: The translational and rotational kinetic energies are related, but the yo-yo is not rolling on its outer radius.]
______s

2007-11-07 11:55:50 · 1 answers · asked by Anonymous

Imagine a parallel circuit with 3 lamps in each branch. Connected to the circuit is an ammeter and a constant-voltage d.c. supply. Each bulb operates at normal brightness and the ammeter (of negligible resistance) registers a steady current.

Then, the filament of one of the bulbs breaks. What happens to the ammeter reading and to the brightness of the remaining bulbs?

The answer is that the ammeter reading decreases and the bulb brightness remains unchanged.

I don't understand why the ammeter reading decreases and why the bulbs' brightness remain the same. I thought the bulbs' brightness will be increased cos one of the filament of the bulb breaks so more current will flow through the other 2 bulbs, isn't it? With more current, shouldn't the other two bulbs shine more brightly? Please answer my 2 questions stated above, thanks.

2007-11-07 11:48:33 · 8 answers · asked by ♪£yricảl♪ 4

He is a terrible teacher and wastes about 3/4 of the class time just finding out the answers to his own practice problems

it literally takes us 35 minutes to go over like 2 simple problems

2007-11-07 11:43:42 · 1 answers · asked by big mike 2

An aircraft carrier launches an airplane with mass 1.12 x 10^4 kg by taking it from rest to 79 m/s over a distance of 159 m. The net unbalanced force required to produce this acceleration is_ N.

(Check the number of significant figures.)

2007-11-07 11:43:38 · 1 answers · asked by Anonymous

i am trying to write an essay and i dont know how some of the people like michael faraday, lisa meichner,marie ann lavoisier, james maxwell, and emilie du chatelet helped albert einstein with his creations. i have to write this paper by tomorrow and i am freaking out. please someone please help me and please quick!!!!!! thanks everyone.

2007-11-07 11:27:30 · 2 answers · asked by lilyellowpimp 2

0.03Lor .00503L

2007-11-07 10:37:34 · 1 answers · asked by rachel 1

There is a ramp with height "h". There is a box at the top of the ramp and it starts at rest, v0=0. There is no friction on the ramp. The catch is that this ramp is in a moving truck, moving at velocity "u". Once the box is released, it moves at it's own velocity "v" plus the velocity of the truck "u", if I am correct. So the total kinetic energy of the box should be: K=(1/2)mu^2+(1/2)mv^2 or (1/2)m(u^2+v^2). However, I looked at the back of the book and the answer says (1/2)m(u+v)^2, which is not equal to the other equation. What did I do wrong? If you need further explanation please ask me. I am in dire need of help!

2007-11-07 10:30:47 · 1 answers · asked by texasrag31 1

A 3.30-kg block of wood rests on the muzzle opening of a vertically oriented rifle, the stock of the rifle being firmly planted on the ground. When the rifle is fired, an 7.88-g bullet (velocity = 8.30 102 m/s, straight upward) becomes completely embedded in the block.
the velocity of the block/bullet system immediately after the collision.is 1.977

Ignoring air resistance, determine how high the block/bullet system rises above the muzzle opening of the rifle.
? m

2007-11-07 10:25:34 · 1 answers · asked by Anonymous

A 7.27 g bullet is fired vertically into a 1.16 kg
block of wood.
The bullet gets stuck in the block, and the
impact lifts the block 0.39 m up. (That is, the
block - with the bullet stuck in it - rises
0.39 m up above its initial position, and then
falls back down.)
Given g = 9.8 m/s^2. What was the initial
velocity of the bullet? Answer in units of
m/s.

2007-11-07 09:39:12 · 2 answers · asked by lilprincess_2good4u 1

Assume a major league baseball pitcher can pitch at 85 miles per hour. If he could pitch that fast straight upward, from what height must a ball be dropped so that the ball pitched and the ball dropped hit the ground at the same time? (Hint: there are 5280 feet in 1 mile)

2007-11-07 09:36:28 · 3 answers · asked by NYcubsfan 1