Physics - April 2007

A car of weight 1.0000×10^4 N car comes to a bridge during a storm and finds the bridge washed out. The driver of weight 650 N must get to the other side, so the crazy bastard decides to try leaping it with his car. The side the car is on is 19.5 m above the river, while the opposite side is a mere 1.60 mabove the river. The river itself is a raging torrent 60.0 m wide.

How fast should the car be traveling just as it leaves the cliff in order just to clear the river and land safely on the opposite side? (Take the free fall acceleration to be g = 9.80 m/s^2)

What is the speed of the car just before it lands safely on the other side? (Take the free fall acceleration to be g = 9.80 m/s^2)

2007-04-16 20:20:39 · 1 answers · asked by Anonymous

An electron of mass 9.11×10^−31 kg leaves one end of a TV picture tube with zero initial speed and travels in a straight line to the accelerating grid, which is a distance 2.15 cm away. It reaches the grid with a speed of 3.60×106 m/s. The accelerating force is constant.

Find the acceleration.

Find the time to reach the grid.

Find the net force. (You can ignore the gravitational force on the electron).

2007-04-16 19:12:26 · 2 answers · asked by Anonymous

Here is the link to the problem/map:
http://www.jburroughs.org/science/mschober/em2-potential/E2_ws3.pdf

I understand the rest but I need help with questions 1 and 2

2007-04-16 19:07:35 · 3 answers · asked by Isabella 3

The current through the battery is 2.0 A. Find the current in the 2.3Ω resistor?
Can someone help me tackle this problem?

2007-04-16 18:29:20 · 5 answers · asked by Anonymous

A car of weight 1.0000×10^4 N car comes to a bridge during a storm and finds the bridge washed out. The driver of weight 650 N must get to the other side, so the crazy bastard decides to try leaping it with his car. The side the car is on is 19.5 m above the river, while the opposite side is a mere 1.60 mabove the river. The river itself is a raging torrent 60.0 m wide.

How fast should the car be traveling just as it leaves the cliff in order just to clear the river and land safely on the opposite side? (Take the free fall acceleration to be g = 9.80 m/s^2)

What is the speed of the car just before it lands safely on the other side? (Take the free fall acceleration to be g = 9.80 m/s^2)

2007-04-16 18:15:50 · 1 answers · asked by Anonymous

Okay, I have a bunch of problems like this in my homework; if you can show me how to work out one, I should be able to work out the others like it.

A 10.0 kg block of metal measuring 12.0 cm x 10.0 cm x 10.0 centimeters is suspended from a scale and immersed in water. The 12.0 cm surface is vertical, and the top of the block is 5.0 cm below the surface of the water.


Using P(0)=1.013x10^5 N/m^2, what are the forces acting on the top and bottom of the block?

What is the reading of the spring scale?

Show that the buoyant force equals the difference between the forces at the top and bottom of the block.


Help is much appreciated, but please don't just give me an answer (I can get that from the back of the book!)

Thanks!

2007-04-16 17:25:37 · 3 answers · asked by Anonymous

2007-04-16 17:13:49 · 7 answers · asked by minki 1

A penny is placed on turntable at a radius of 12 cm. The turn table rotates with a period of 1.8 seconds. What is the acceleration? I got 1.77, but the answer was 1.74. What should I have done to get that answer?

2007-04-16 17:02:56 · 3 answers · asked by melanie s 2

All I need is just examples and I will search for each example I find here.

2007-04-16 16:21:37 · 5 answers · asked by Anonymous

If an electron moved from 0V potential to 10V potential, would its potential energy increase or decrease? If a proton moved from 0V potential to 10V potential, would its potential energy increase or decrease? Please give an explaination of why.

2007-04-16 16:12:07 · 2 answers · asked by Jonathan 1

I'd like a very simple answer just to give me an idea of what i have to do. Or a link to a web site that explains it in a simple way, like "coils for dummies" or something like that. I want to produce a voltage with a permanent magnet.

2007-04-16 16:09:57 · 2 answers · asked by Richie Gonzales 1

One end of a uniform 4.20 m long rod of weight Fg is supported by a cable. The other end rests against the wall, where it is held by friction. The coefficient of static friction between the wall and the rod is µs = 0.495. Determine the minimum distance x from point A at which an additional weight Fg (the same as the weight of the rod) can be hung without causing the rod to slip at point A (where the rod intersects with the wall).

2007-04-16 16:06:22 · 1 answers · asked by wills 3

I just wanted to know why equations like W=Fd, W=∆E, Ep = mgh, or Ek = 1/2 mv2 are important and applicable in real life

2007-04-16 15:45:30 · 2 answers · asked by skybluu 2

Hi,

A steel wire is used to stretch a spring. An oscillating magnetic field drives the steel wire back and forth. A standing wave with three antinodes is created when the spring is stretched 7.5 cm. What stretch of the spring produces a standing wave with five antinodes?

I know that the length has to be shorter than 7.5 cm. How would I go about calculating it?


Thanks!

2007-04-16 15:19:51 · 1 answers · asked by Anonymous

2007-04-16 14:27:21 · 1 answers · asked by Morgan 1

Tell me anything and everything that you know about any of the following

a) gravity
b) atoms
c) light
d) quantum theory
e) motion
f) higgs boson
g) matter and antimatter
h) four forces

you are not required to answer all of them you know

2007-04-16 13:56:52 · 3 answers · asked by The Ponderer 3

if matter is anything that has mass and takes up space, and mass is a measurement of how much matter something contains, how can something like a gluon, photon etc not have mass? its like saying its 'something' but its made up of 'nothing.'

2007-04-16 13:07:18 · 5 answers · asked by Anonymous

the bottom of a steel boat is a 5 m x 10m x 2 cm piece of steel (rho steel 7900 kg/m^3 ) the sides are made of 0.50 cm thick steel. what minimum height must the sides have for this boat to float in perfectly calm water??

plzz guys i need help.....could u explain it ...thanks

2007-04-16 12:54:08 · 2 answers · asked by Anonymous

Two masses (mA= 2 kg, mB= 4 kg) are attached to a (massless) meter stick, at the 0 and 75 cm marks, respectively.

a.) Where is the center of mass of this system?
cm, from mass A.

b.) The system is then hung from a string, so that it stays horizontal. Where should the string be placed?
cm, from mass A.

c.) Now, if mass B was removed, how much force would need to be exerted at the 100 cm mark in order to keep the meter stick level*?
N, ---Select--- upwards. downwards.

d.) Now, if mass B was removed, and no additional force was supplied, calculate the size of the angular acceleration of the meter stick at that instant*.
rad/s2

*For parts c-d, assume the string remains attached at the same location you found in part b.

answer my other questions posted.

2007-04-16 12:32:14 · 3 answers · asked by soccerjock 2

a partical is located at the vector position 2.2m + 4m and the force acting on it is 3.4N + 2.7N. what is the magnitude of the torque about the point having coordinates [2m,9m] ?

2007-04-16 11:55:25 · 2 answers · asked by Anonymous

Any answers or websites are great

2007-04-16 11:47:42 · 4 answers · asked by Jane A 3

please answer because i would like extra credit

2007-04-16 11:42:44 · 5 answers · asked by sarge_led 1

a 1200 kg car starts from rest and accelerates to 72 km/h in 20s. Friction exerts an average force of 450 N on the car during this time.
So: t=20s m=1200kg F=450N v=20 m/s (i converted it) a=9.8 m/s^2
A) What is the net work done on the car? B) How far does the car move during its acceleration?
Okay so for part A I used the equation d=d(subzero)+1/2(v:subzero+ v)t. But I overheard my teacher say that you have to square the 20. Then use W=Fd. So then I figured I could use d=1/2at^2. (the t is 20) Then use W=Fd and figure out the work.
Okay so for B) the answer is 200m. If you use d=1/2at^2 you don't get a distnace of 200. But, if you use d=d(subzero)+1/2(v:subzero+ v)t then you get a distance of 200m. But that won't make me square the 20 for part A. So...... What do I do? I have two distance formulas that don't give me the same distance.

Please show me work and what not. Thanks so much.

2007-04-16 11:32:23 · 4 answers · asked by becca h ♥ 2

A signal rocket is launched vertically at a velocity of 80 m/s
Calculate:
a) The time taken to reach its maximum height
b) The maximum height reached
c) The velocity at a height of 27m
d) Its height after 5 seconds

2007-04-16 11:16:17 · 2 answers · asked by MoLeY 1

if so please explain.

2007-04-16 11:02:02 · 5 answers · asked by delkkis 1

a 60kg skier starts from rest at the top of a 65m high slope. A) If frictional force do -10.5 J work how fast is she going at the bottom. B) Now moving horizontally the skier crosses a patch of soft snow where the Uk =.20. If the patch is 82 mwide and the asverage force of air on the ski is 160N how fast is she going after crossing the patch. C) the skier hits a snowdrift and penetrates 2.5 m into it before stopping. what is the average force exerted on her by the snow drift

2007-04-16 10:40:14 · 1 answers · asked by Cris 1

An 8.40 kg block travels on a rough horizontal surface and collides with a spring. The speed of the block just before the collision is 4.00 m/s. As it rebounds to the left with the spring uncompressed, the block travels at 3.00 m/s. The coefficient of kinetic friction between the block and the surface is 0.360.
(a) Determine the magnitude of the loss in mechanical energy due to friction while the block is in contact with the spring.
_29.4_ J

(b) Determine the maximum distance the spring is compressed.
___ m

I have the 1st answer, but I'm stuck on the 2nd one. I'm really bad at these. Please help! Thank you!

2007-04-16 10:22:52 · 2 answers · asked by Anonymous

a real inverted image I of an object O is formed by a certain lens; the object-image seperation is D=40.0 cm, measured along the central axis of the lens. The image is just half the size of the object. (a) what kind of lens must be used to produce this image. (b) how far from the object myst the lens be placed (c) what is the focal length of the lens.

o (arrow pointing upward)____________________________axis
I (arrow pointing downward)
d is length between o and i lens is in the middle.

so if the image is real does the lens have to be convexed isn't that what it takes to get a real inverted image? please help me with all of this thank you soo much

2007-04-16 10:13:57 · 1 answers · asked by bwaystar123 2

1. find the acceleration of the shell. 2. find the friction force on it. 3. if the mass increased to 4 kg find the acceleration of the shell and the friction force on it.

2007-04-16 09:43:40 · 2 answers · asked by Melissa 1

Well you know, the astronauts train by simulating antigravity in a plane, with a big fan or in a big swimming pool, but why they havent create an antigravity chamber or something like that. Something that eliminates the gravity attraction in a place of the planet.

2007-04-16 09:26:28 · 8 answers · asked by Anonymous