Physics - September 2007

the acceleration of a particle is directly proportional to the time t.at t =0 velocity =400mm/s.
knowing that at t=1 velocity =370mm/s and distance = 500mm
determine the velocity, the position and the total distance traveled when t = 7s

im not sure if what i have done is correct, i got -60 as the constant which gave velocity at 7s = -1070

can anyone please help?

2007-09-17 10:00:45 · 1 answers · asked by Anonymous

I need some quick help to a physics problem.

1) A car is moving at a constant velocity to the right

There is the force of air resistance and the force of the road on the car. (as well as gravity and normal force).

My question is...would the force air and force road be equal because the velocity is constant?


2) If the car is speeding up would the force from the road be greater or less than the force of air resistance?

(it doesn't mention friction in this problem but I'm assuming that's factored into the force of the road pushing back on the car and the spinning of the tires, engine etc)

And then if it's slowing down, same question-- which force would be greater: the force of the road or the force due to air resistance?


Thanks so much to all who answer!
I will be sure to choose a Best Answer!

2007-09-17 09:51:59 · 3 answers · asked by Anonymous

Hi,

if there was a space station and its mass is 2.09x10^4 kg and it orbits the Earth with a height of 350km. The radius of the Earth is 6400km. How would I be able to work out the angular displacement (in radians) after 1 hour?

I've already worked out the centripetal force on the space station, its orbital speed and the time taken for each orbit but not quite sure how I can use these to calculate this last question. Please advise. Many thanks.

2007-09-17 09:51:33 · 1 answers · asked by Anonymous

2007-09-17 09:40:51 · 1 answers · asked by Anonymous

An airplane is flying at 150 mi/hr (its speed in still air) in a direction such that a wind of 60 mi/hr blowing east to west, the airplane travels in a straight line southward....

what must the plane's heading direction for it to fly diredtly south?...

how do you do this?... i thought that i could add the Vector of the plane relative to the earth with the Vector of the wind relative to the earth to get the resultant, answer... but don't i need at least one angle to do that? or am i over thinking it and there is an easier way to figure this out... please help
thank you...

2007-09-17 09:40:46 · 2 answers · asked by hidden_within_a_nightmare 3

Hi few questions on how these are done, for my college Engr 10 class ( intro to Engr). Please tell me equations and show how done.

1. A person running at the pace of 5mph expends 300 kilocalories of energy per hour.

a)Find the power of the runner is exerting while running.

b)Find the total energy exerted by the runner in a 10k run

I got 343.02 kc is that right?


2. It took you 2 hours to drive to Berkeley and back with a total distance of 100 miles traveled

a) Your car gets 34.0 miles per gallon. How much energy have used for this trip?

b) What is the average power consumption for this trip?

c) We know that energy does not vanish ( energy conservation). Where does the energy go ( consumed) after the trip?

2007-09-17 09:14:28 · 3 answers · asked by Ali G 1

what is the scientific method called and how does it work

2007-09-17 08:47:49 · 7 answers · asked by helen m 1

What is the purpose of the four red rods shown in the picture?
http://tinypic.com/view.php?pic=5xpy4o3

2007-09-17 08:47:01 · 3 answers · asked by Alexander 6

i just curious cuz how is it supposed to stick lol xD

2007-09-17 08:26:29 · 4 answers · asked by Anonymous

2007-09-17 08:07:35 · 6 answers · asked by  the purple duck 5

A soccer ball is kicked from the ground with an initial speed of 20.8 m/s at an upward angle of 48.0°. A player 40.6 m away in the direction of the kick starts running to meet the ball at that instant. What must be his average speed if he is to meet the ball just before it hits the ground? Neglect air resistance.

2007-09-17 07:23:37 · 2 answers · asked by James B 1

Does time exist in space?

2007-09-17 07:21:35 · 4 answers · asked by vince_oy 3

(a) If the maximum acceleration that is tolerable for passengers in a subway train is 1.74 m/s2 and subway stations are located 836 m apart, what is the maximum speed a subway train can attain between stations? (b) What is the travel time between stations? (c) If a subway train stops for 24.0 s at each station, what is the maximum average speed of the train, from one start-up to the next?

2007-09-17 07:19:14 · 1 answers · asked by James B 1

http://mlf1070.wordpress.com/2007/08/27/finding-god-in-physics/

Any scientists of any field want to help clarify any misconceptions in this essay?

2007-09-17 07:14:44 · 6 answers · asked by Anonymous

I want to help revolutionize particle physics ! I know one trait, creativity, is a big one.. Any relevant thoughts, tips, etcetera would be great!

2007-09-17 06:56:12 · 5 answers · asked by justanotherfreak 1

In the Daytona 500 auto race, a Ford Thunderbird and a Mercedes Benz are moving side by side down a straight-away at 72.5 m/s. The driver of the Thunderbird realizes that she must make a pit stop, and she smoothly slows to a stop over a distance of 250 m. She spends 5.00 s in the pit and then accelerates out, reaching her previous speed of 72.5 m/s after a distance of 340 m. At this point how far has the Thunderbird fallen behind the Mercedes Benz, which has continued at a constant speed?

2007-09-17 06:55:44 · 1 answers · asked by Foxychick 1

A small charged sphere of radius a=1.00 cm is suspended by a nylon thread inside a larger neutral, conducting sphere. The larger sphere has an interior radius b=3.10 cm and is Δ=0.5 cm thick. The charge on the small sphere is q=0.90 nC. The two spheres are concentric and insulated from their surroundings. For the following questions, the origin of our coordinates is the center of the spheres.


1) What is the magnitude of the electric field at a radius 10.0 cm? Hint: Use Gauss's law, and remember that the outer sphere is neutral

2) What is the magnitude of the electric potential at the surface of the smaller sphere?

3) What is the magnitude of the electric potential at the outside surface of the larger sphere?




i can't figure these three out for some reason, pelse help

2007-09-17 06:28:34 · 2 answers · asked by chs_soccer_02 2

1) A charge of 0.821 nC is placed at the origin. Another charge of 0.395 nC is placed at x1 = 12.9 cm on the x-axis


At which point on the x-axis does this potential have a minimum?


i dont get how to do this problem

2007-09-17 06:22:20 · 2 answers · asked by chs_soccer_02 2

Calculate the magnitude and direction of the resultant force on an object that is acted on by a force of 4.0 N and a force of 10 N, that are

a) in the same direction

b) in opposite directions

c) at right angles to each other.

AS Physics Homework, thanks.

2007-09-17 06:14:35 · 3 answers · asked by Anonymous

2007-09-17 06:04:27 · 1 answers · asked by Courtney P 1

A ship leaves port A, and travels a distance of 60km due North, it then changes direction at B and travels a distance of 20km due East to a second port C.

a) Calculate the direct distance from A to C

b) Calculate the angle between due North and the line from A to C.

AS physics homework, I'm really stuck, need help quickly. Any useful help, will be appreciated.

2007-09-17 06:03:30 · 4 answers · asked by Anonymous

At what point do you just give up on wrapping your mind around something and forget the you pondered it in the first place?

2007-09-17 06:01:51 · 5 answers · asked by Anonymous

what if your approaching earth, does gravity increase at any point? perhaps the interior of earths core has more gravity than the surface?

2007-09-17 05:50:06 · 6 answers · asked by Backtash123 1

When you rest your forehead on a pole and spin round and round, then try and walk in a straight line, you always stumble. How many revolutions would it take so that when you let go of the pole and try and step forward you fall over?

2007-09-17 05:46:58 · 10 answers · asked by Gem Gem 5

how can we feel WAITLESS on earth

2007-09-17 05:28:58 · 19 answers · asked by Anonymous

1.) The height of a helicopter above the ground is given by h = 2.65t3 , where h is in meters and t is in seconds. After 2.05 s, the helicopter releases a small mailbag. How long after its release does the mailbag reach the ground?

2.) A car accelerates at 2.25 m/s2 along a straight road. It passes two marks that are 27.0 m apart at times t=3.85 s and t=4.90 s. What was the car's velocity at t=0?

3.) A parachustist jumps from an airplane and freely falls y=54.6 m before opening his parachute. Thereafter, he decelerates at a=1.71 m/s2. As he reaches the ground, his speed is
3.12 m/s. How long was the parachutist in the air?

4.) At what height did the parachutist jump from his plane?

5.) A very silly person, intent on catching pigeons on the roof of an apartment building, trips and falls a distance of 44.0 m. She lands on a metal garbage can, crushing it to a depth of
0.479 m and walks away without having been seriously hurt. What acceleration did she exp

2007-09-17 05:21:38 · 1 answers · asked by killakam 1

It's been a while I took Physics and, being an engineering course, the emphasis was on Newtons's Physics.

In a relativistic context, how should we interpret classical equations like f = ma (f, force, m mass, acceleration). Is it still true that v = ds/dt (v the velocity vector, s the dsplacement vector and t the time). I think this has to do with Lorentz transform, right?

In electromagnetism, are results like Maxwell's equations and Biot Savat Law still valid?

Thank you

2007-09-17 04:38:28 · 6 answers · asked by Steiner 7

Two charges are placed as shown in the figure (a right triangle with the right angle at point P). The distance between charges is 13.0 cm. Point P is 5.0 cm from the charge q1 and 12.0 cm from the charge q2. The magnitude of is 3.00uC , but its sign and the value of the charge q2 are not known. The direction of the net electric field at point P is entirely in the negative y-direction.

Determine the magnitude of the electric field.

2007-09-17 03:23:45 · 2 answers · asked by Hannah 4

If body A is sliding over B due to an accelerating force, then A will have a constant velocity when

A. Kinetic friction equals the accelerating force
B. Equilibrium does not exist
C. Static friction equals the accelerationg force
D. the normal force equals zero

2007-09-17 03:13:55 · 3 answers · asked by CarzCrashzHeartz 3

Two crewmen pull a boat through a lock. One crewman pulls with a force of F1 = 105 N at an angle of = 33° relative to the forward direction of the raft. The second crewman, on the opposite side of the lock, pulls at an angle of 45°. With what force F2 should the second crewman pull so that the net force of the two crewmen is in the forward direction?

2007-09-17 02:45:33 · 2 answers · asked by Anonymous