Physics - September 2007

Small spacecraft travelling in deep space. Not subject to gravitational field

the craft is moving at constant velocity = 250 m/s
in the positive x direction. It fires a thruster for a period of 10 s during which time it gives the spacecraft a constant acceleration of 7 ms^-2 in the negative x direction.
What is the velocity of the craft at the
end of this time (I got v = 180 m/s)

A 2nd thruster is fired which gives the craft a constant acceleration of 12 ms^-2 in the + y direction

1. How long will the 2nd thruster have to fire in order
that the speed of the space craft should reach 300 m/s

2. In what direction is the spacecraft travelling
when this speed is attained

2007-09-19 05:28:00 · 1 answers · asked by   4

A satelite moves round the earth at constant speed on a circular orbit of radius 8000 km, with a time period of 120 minutes. Calculate its orbital speed in ms-1.

AS Physics homework, thanks.

2007-09-19 05:21:59 · 3 answers · asked by Anonymous

A woman at an airport is towing her 23.0 kg suitcase at constant speed by pulling on a strap at an angle of θ above the horizontal. She pulls on the strap with a 36.5 N force, and the friction force on the suitcase is 20.0 N.

(b) What angle does the strap make with the horizontal?

(c) What normal force does the ground exert on the suitcase?

2007-09-19 05:13:54 · 2 answers · asked by surfing86 2

A 1.00 kg object is observed to have an acceleration of = 19.0 m/s2 in a direction θ = 33.0° north of east. The force 2 acting on the object has a magnitude of 10.3 N and is directed north. Determine the magnitude and direction of the force 1 acting on the mass.

2007-09-19 05:12:49 · 1 answers · asked by surfing86 2

Lets assume that planet Earth is the only massive body around here, and moves at speed 1km/s towards a huge field of almost motionless small rocks. The concenteration of rocks is 1 rock per 1,000,000 km³ (n = 1e-6/km³).

http://i16.tinypic.com/4vefxjr.jpg

What will be the rate of bombardment of the entire planet (rocks per second) when it enters the field?

2007-09-19 04:53:30 · 2 answers · asked by Alexander 6

You toss a chocilate bar to your hiking companion located 8.6 m up a 39 degree slope.determine the initial velocity vector so that chocolate bar will reach your friend moving horizontal??

2007-09-19 04:49:05 · 5 answers · asked by M R 1

it is the push or pull but when we apply force on aaa downward table why dont we see any efect of force?

2007-09-19 04:45:34 · 2 answers · asked by A`A A 1

a stone falls from rest from the top of a high cliff. a second stone is thrown downward frm the same height 2 s later with an initial speed of 30 m/s.if both stones hit the ground simultaneously,how high is the cliff?assume a constant acceleration magnitude g= 9.8 m/s2

2007-09-19 03:54:38 · 4 answers · asked by huwaida b 1

FIghter pilots and submarine officers have their own way of representing vectors, and they do it three dimensions. Their survival depends on understanding vector approaches instead of saying an airplane is travelling of 400km/hr westward they usually say something like "Bogeys 10 click at 5'o clock high" "check your sives" or "unidentified object detected at 75 mark 8". How do these people represet magnitude and direction?

2007-09-18 23:35:42 · 2 answers · asked by mhark e 1

A brick falls freely from a high scaffold and hits the ground 3.5 seconds. How high is the scaffold? What is the velocity of the brick just before hitting the ground?

please give the step by step solution with formula..thank you!

2007-09-18 22:43:04 · 5 answers · asked by Anonymous

I was kind of bothered by this. Newtons first law states that Force is equaLs to mass multiplied with acceleration. Tomove an object you need to exert force. Assume that we have a car moving constantly at the speed of 60mph. Since I said constant, then it means there would be no acceleration right? Since there's no acceleration, 0 m/s2 multiplied by the mass of the car would mean that there's no force or F = 0, right? Then, why would a car going at constant 60mph would hit a man and would send the man flying? The speed was constant, and there was no acceleration, which means no force, but why did the car move the man when in fact you need force to move something. Does this mean that I proved that Newton's law is quite wrong?

2007-09-18 21:48:36 · 11 answers · asked by love_doctor 4

i'm talking about someone who will totaly chainge man outlook on something.

2007-09-18 21:47:39 · 12 answers · asked by strongbow 3

a body moving with uniform acceleration has a velocity of 15.6cm/s when its x coordinate is 4.28cm. if its x coordinate 2.82s later is -8cm, what is the magnitude of acceleration? answer in units of cm/s^2.

2007-09-18 19:53:03 · 4 answers · asked by michael v 1

A particle moves along the x axis according to the equation x = 2.05 + 2.94t - t2, where x is in meters and t is in seconds.
(a) At t = 2.80 s, find the position of the particle.
m
(b) What is its velocity?
m/s
(c) What is its acceleration?
m/s2

2007-09-18 19:39:57 · 3 answers · asked by inpsite 1919 3

If the Hubble telescope can zoom out millions of light years away into the infinite univerese then how "far" can the best microscope zoom in on a object. What is beyong the atoms and/or "strings."

2007-09-18 19:15:46 · 8 answers · asked by bigpapamarek 1

i.e., what does a graph of the relationship look like if the x-axis is the mass??

2007-09-18 18:47:41 · 5 answers · asked by Anonymous

(b) What is the change of potential energy as a result of this move? (c) How much kinetic energy will the crate have as it falls and hits the floor?

2007-09-18 18:11:34 · 5 answers · asked by sojo3 1

Describe how can its magnitude be calculated?

2007-09-18 18:10:26 · 3 answers · asked by sojo3 1

The temperature drops about 2 degree F for every rise of 530 ft. in altitude . Some guy acheived the altitude record of 64,997 ft. in a hot-air balloon. About how many degrees difference was there between the ground temperature and the air temperature? PLEASE HELP ME!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

2007-09-18 18:10:06 · 3 answers · asked by sassyblondgirl94 1

A mountain climber, in the process of crossing between two cliffs by a rope, pauses to rest. She weighs 590 N. As the drawing shows, she is closer to the left cliff than to the right cliff, with the result that the tensions in the left and right sides of the rope are not the same. Find the tensions in the rope to the left and to the right of the mountain climber.

2007-09-18 16:45:05 · 1 answers · asked by Lisa B 1

What angle does Fr make with the positive x axis?
Fr=1.8 N
Three forces of magnitudes F1=4.0N,F2=6.0N , and F3=8.0N are applied to a block of mass , initially at rest,
F1 is at an angle of 25 degrees
F2 is at an angle of 10 degrees(in the - y direction)
F3 is at an angle of 235 degrees

2007-09-18 15:53:56 · 2 answers · asked by Anonymous

where he started. The first displacement is 8.00 m westward, and the second is 12.0 m northward. Use the graphical method to find the magnitude and direction of the third displacement. the magnitude is 14.422m and I can't find the angle.....the angle is (clockwise from due north)

2007-09-18 15:46:08 · 1 answers · asked by hockeywinger14 1

If a small planetoid in a disk of debris is orbiting around or spiraling in on the Sun, the debris outside of it will be going slower than the planetoid and the debris inside the planetoid will be going faster. As the debris is drawn to the planetoid by gravity, will the incoming debris result in a planet that spins clockwise or counterclockwise and why? I don't have the Physics to evaluate the effects of the Sun's gravity pulling one way on the debris and the planetoid's pulling the other. We're looking down on the system from above of course.
I know that if the whole disk has the same angular velocity that the planet will end up spinning counterclockwise like we do.

2007-09-18 15:44:46 · 2 answers · asked by dukebaker 1

2007-09-18 15:44:28 · 1 answers · asked by JAMES 4

the weight of the block on the table is 476 N and that of the hanging block is 180 N. Ignore all frictional effects, and assume the pulley to be massless.
Find the acceleration of the two blocks. ?
Find the tension in the cord ?

2007-09-18 15:41:57 · 1 answers · asked by Anonymous

I'm having a hard time understanding probability. I always thought that probability doesn't really exist, it was just a idea we came up with. I've always thought that if we had a time machine and kept going back in time to observe a specific event it would end up playing out the same way every time

But now i had someone try and explain uncertainty to me and I’m confused.

Is there really such a thing as a random occurrence or is there only one possible way for every event in the universe to play out?

I'm looking for a physics based answer not a philosophical one. Thanks

2007-09-18 15:38:42 · 4 answers · asked by Russ 2

2007-09-18 15:27:33 · 1 answers · asked by To-the-Stars 4

matter neither gained or destroyed, hmm.?

2007-09-18 15:18:46 · 2 answers · asked by ihaveques 2

A certain freely falling object requires 1.45 s to travel the last 25.5 m before it hits the ground. From what height above the ground did it fall?

2007-09-18 15:14:14 · 1 answers · asked by lisyaoran 2

motion relative to the bus and relative to a point on the ground

2007-09-18 14:53:42 · 2 answers · asked by schuggyt 1