Physics - October 2007

2007-10-16 19:35:55 · 7 answers · asked by Raian Razal 3

A 1.7 kg body is initially moving northward at 15 m/s. Then a force of 20 N, toward the east, acts on it for a time of 4.5 s.

(a) At the end of that time, what is the body's final velocity?
Magnitude________m/s
Direction_________° north of east
(b) What is the change in momentum during that time?
__________kg*m/s

2007-10-16 19:33:28 · 3 answers · asked by Anonymous

where is black hole located ??? in the middle of our galaxy? or somewhere in our universe???

2007-10-16 19:12:02 · 6 answers · asked by watani@sbcglobal.net 1

m=.03579 kg
v=355 m/s

What will the kinetic energy be in 18.49 seconds?

I know how to find the kinetic energy, but i just don't know how to factor in time.

2007-10-16 18:44:42 · 4 answers · asked by Anonymous

I'm more confused on part (a.) on how to answer the question more than anything else, here is the whole thing:

A car initially traveling eastward turns north by traveling in a circular path at uniform speed as in the figure below. The length of the arc ABC is 210 m, and the car completes the turn in 32.0 s.

(a) What is the acceleration when the car is at B located at an angle of 35.0°? Express your answer in terms of the unit vectors and .

(b) Determine the car's average speed.

(c) Determine its average acceleration during the 32.0 s interval.

-------------------------------------

I've tried answering part B without answering part a. which I assumed that the ABC arc was just another type of radius and thus r=210m and that my angle would just become 35 degrees. Then I solved for Velocity with the F= m(v^2/r) got the velocity which due to shortage of characters my answer which was incorrect was 37.96 m/s, so I'm stumped currently.

Appreciate the help. :+)

2007-10-16 18:10:29 · 4 answers · asked by Anonymous

What would happen if a person fell from a building and, on the way down, grabbed a high-voltage wire? If the wire supports him as he hangs, will he be electrocuted?

Finally, if the wire breaks, should he continue to hold onto the end of the wire as he falls?

Thanks

2007-10-16 18:04:39 · 11 answers · asked by Anonymous

In this problem...What is the force of gravity between you and the earth...what would be the value of "r" in the equation for Newton's law of universal gravitation...i thought it would be zero since we are on the earth but zero can't be in the denominator so i'm stumped...can anyone help me out?

2007-10-16 18:04:06 · 4 answers · asked by k_hrdr 2

Suppose there is a planet that is tidally bound to its star, much like our moon is locked to the earth. If the conditions were right for the average temporature of the planet to sustain liquid water, then would all the acumilation of ice on the dark side cause the planet to change its rotation?

2007-10-16 17:44:52 · 2 answers · asked by bricolage 1

sheets tied together can support a mass of only 58 kg. How might the thief use this "rope" to escape? Give a quantitative answer.

2007-10-16 17:33:27 · 3 answers · asked by Hu-Li X 1

A person pushes on a stationary 125 N box with 75 N at 30 degrees below the horizontal. The coefficient of static friction between the box and the horizontal floor is 0.80.

http://tinypic.com/fullsize.php?pic=2en3wvm&s=2

2007-10-16 17:21:00 · 1 answers · asked by sandymandy 1

A 3.00kg ball is dropped from rest from the roof of a building 176.4m high. While the ball is falling, a horizontal wind exerts a constant force of 12.0N on the wall. How long does the ball take to hit the ground?

2007-10-16 17:12:01 · 2 answers · asked by jalisamarie12 1

Two crates connected by a rope of negligible mass lie on a horizontal surface. (See the figure.) Crate A has mass x and crate B has mass y . The coefficient of kinetic friction between each crate and the surface is u. The crates are pulled to the right at a constant velocity of 3.2 m/s by a horizontal force .

in terms of x, y, and u find the magnitude and tension

http://tinypic.com/fullsize.php?pic=xp7odi&s=2

2007-10-16 17:10:13 · 1 answers · asked by kiranrai98 1

Two objects of equal mass are on a turning wheel. Mass 1 is located at the rim of the wheel while mass 2 is located halfway between the rim and the axis of rotation. The wheel is rotating at a constant angular velocity. For each of the following statements select the correct option:

[The options for each blank are =, >, <, or cannot determine.]

For a given time, the angle covered by mass 1 is ____ mass 2.
The moment of inertia of mass 2 is ___ the moment of inertia of mass 1. (Both moments of inertia are taken about the axis of rotation.)
The speed of mass 2 is ____ mass 1.
The radial acceleration of mass 2 ____ the radial acceleration of mass 1.
The tangential acceleration of mass 2 ____ the tangential acceleration of mass 1.
For a given time, mass 1 travels a distance ____ mass 2.

2007-10-16 16:59:31 · 1 answers · asked by soulshifter_666 1

2007-10-16 16:56:25 · 5 answers · asked by Anonymous

I need help to understand exactly what the paper talks about. I'm Leon's great-nephew, and I plan on taking up his work. I understand he mathamatically proved that Newman's machine was possible, and that you could propel objects around Earth with merely Gravity and the Coriolis Effect. I need explanations for these terms and the paper.

2007-10-16 16:50:25 · 2 answers · asked by Anonymous

Submarines can dive from the surface of the water to depths of up to 1,200 feet, then can rise to the surface again, but why can they do this over and over again? When they put water in the compartments to sink the sub, where does the air go? When they pump out the compartments to rise to shallower depths, where does the air come from? After all, they are under water. So, how is a submarine able to do all of this?

Also, can anyone help me find a diagram from a website that explains all of this?

2007-10-16 16:47:07 · 2 answers · asked by Sarah S 3

In magnetic induction,

why is the outgoing peak of a graph higher than the incoming peak for one run??

please please help me with this!! thanks

2007-10-16 16:41:50 · 1 answers · asked by Anonymous

Why is it that particles can defy logic, as in the Double-slit experiment? How can an electron go through two slots at once, and interfere with itself? And why, through the act of observing, does the result change? Are subatomic particles aware of their surroundings??

2007-10-16 16:33:22 · 2 answers · asked by Anonymous

explain why a rope climber must pull downward on the rope in order to move upward. discuss the force exerted by the climber's arms in relation to the weight of the climber during the various stages of each "step" up the rope.

2007-10-16 16:29:52 · 2 answers · asked by Anonymous

(a) Vector a =?
(b) Vector b= 25 N
(R) Resulting Vector= 30 N
Theta= 104degrees

i need to solve for vector 'a' and i put it into the equation

b² + R² - 2bR cos(theta)
or
25²N + 30²N - 2(25)(30) cos(104)

but when i put the answer back into the regular equation:
a² + b² - 2ab cos(theta)

it doesnt work out >.< please help! i do best answers!

2007-10-16 16:26:53 · 1 answers · asked by TheLifeOfTheParty 2

I've looked it up, but the terms are so confusing that I don't understand it! Would anyone be able to help me understand it with simple physics terms?

2007-10-16 15:58:51 · 1 answers · asked by Anonymous

A person jumps from the roof of a house 4.5 m high. When he strikes the ground below, he bends his knees so that his torso decelerates over an approximate distance of 0.70 m. The mass of his torso (excluding legs) is 41 kg.
(a) Find his velocity just before his feet strike the ground.

(b) Find the average force exerted on his torso by his legs during deceleration.
Magnitude

2007-10-16 15:54:54 · 3 answers · asked by Anonymous

Yeah, it's from my eighth grade physical science book. can you please explain what it is?

2007-10-16 15:44:54 · 22 answers · asked by Jessica 3

Submarines can dive from the surface of the water to depths of up to 1,200 feet, then can rise to the surface again, but why can they do this over and over again? When they put water in the compartments to sink the sub, where does the air go? When they pump out the compartments to rise to shallower depths, where does the air come from? After all, they are under water. So, how is a submarine able to do all of this?

Also, can anyone help me find a diagram from a website that explains all of this?

2007-10-16 15:35:31 · 1 answers · asked by Sarah S 3

A bullet accelerates at 6.9 x 104 m/s2 from rest as it travels the 0.80 m of the rifle barrel. How long was the bullet in the barrel? What was the bullet's velocity as it left the barrel?

2007-10-16 15:28:34 · 1 answers · asked by Anonymous

A car moving with a constant acceleration covers the distance between two points 60 m apart in 6.0 s. Its velocity as it passes the second point is 15 m/s. How far behind the first point was the car at rest?

2007-10-16 15:15:40 · 1 answers · asked by Anonymous

A basketball player achieves a hang time of 0.517 seconds while dunking a ball. The acceleration of gravity is 9.8 m/s/s
What vertical height will he attain?

2007-10-16 15:14:39 · 1 answers · asked by Zubin S 1

A block is hung by a string from the inside roof of a van. When the van goes straight ahead at a speed of 28 m/s, the block hangs vertically down. When the van maintains the same speed around an unbanked curve (r = 150 m), the block swings toward the outside of the curve. Then the string makes an angle with the vertical. Find this angle.

2007-10-16 14:59:07 · 1 answers · asked by Ariel 2

A block of mass 3.82 kg lies on a frictionless horizontal surface. The block is connected by a cord passing over a pulley to another block of mass 6.4 kg which hands in the air. Assume the cord to be light(massless and weightless) and unstretchable and the pulley to have no friction and no rotational inertia. Acceleration of gravity is 9.8 m/s^2. Calculate the acceleration of the first block? Calculate the tension in the cord answer in Newtons.
my teacher gave me an example with μ but this problem does not give us μ. I think you use this equation
(Mass2)(gravity)-ForceFriction= (masstotal)(acceleration)
Friction Force= μ (mass one)(gravity)
that is the equation i should have used except this problem does not give me μ please help.

2007-10-16 14:46:27 · 2 answers · asked by Anonymous

2007-10-16 14:40:49 · 1 answers · asked by masania 1