Physics - October 2007

Astronauts in the space shuttle in orbit experience weightlessness. Does this mean that there is no gravity in space? Explain what is going on.

2007-10-28 04:34:48 · 4 answers · asked by Anonymous

https://tycho-s.phys.washington.edu/cgi/courses/shell/common/showme.pl?courses/phys114/autumn07/homework/04d/2blocks_incline_NWT/5.gif

The figure shows two identical blocks tied together with a string which passes over a pulley at the crest of the inclined planes, one of which makes an angle q1 = 29° to the horizontal, the other makes the complementary angle q2 = 61°.
a) If there is no friction anywhere, with what acceleration do the blocks move?

a = m/s2
b) If each block has a mass m = 0.7 kg, what is the tension in the string while they are both moving?

T = N
c) Now suppose the coefficient of sliding friction between the blocks and planes is µ = 0.03. With what acceleration do the blocks move in this case?

af = m/s2

2007-10-28 04:03:39 · 1 answers · asked by Anonymous

could u explain please !!

2007-10-28 03:50:22 · 2 answers · asked by Anonymous

monochromatic light of wavelength 3.80 x 10-7m falls with an intensity of 6.0 x 10-6 W m-2 on to a metallic surface whose work function is 3.2 x 10-19J.

a) calculate the energy of a single photon of light of this wavelength
b) the number of photons emmited per second from 1.0 x 10-6 m2 of the surface if a photon has a 1 in 1000 chance of ejecting an electron.

please show me how to do it and not just give me the answer

2007-10-28 03:11:11 · 1 answers · asked by Ricky L 1

Would other beach-goers, surfers, swimmers, saltwater alligators, sea cucumbers and other living things in the sea all around the world be electrocuted too or would it just affect a small area.

If so, how do you determine this area?

2007-10-28 02:52:02 · 2 answers · asked by Six 1

end to reach the speed of light?

degrees= 360
time= 1 sec
length= ?

*no air resistance or gravity

2007-10-28 02:42:33 · 6 answers · asked by tat6504 2

2007-10-28 02:31:06 · 8 answers · asked by Re 1

2007-10-28 02:17:27 · 4 answers · asked by GORAWALIA SHAH 1

A 135.0 kg box is pushed by a horizontal force F at constant speed up a frictionless ramp which makes an angle of 23.0 deg with the horizontal. What is the magnitude of the Normal force between the ramp and the box?

**I found the magnitude of the applied force=561.6 N. For some reason, I can't get the right answer on what the normal force is. If someone could help me that would be great!

2007-10-28 02:04:56 · 2 answers · asked by Anonymous

Can u please provide a detailed explanation.. m totally lost.. thanks:=)

2007-10-27 22:29:07 · 6 answers · asked by Anonymous

A 920 g rock is whirled in a horizontal circle at the end of a 1.5 m-long string.

If the breaking strength of the string is 120 N, what is the maximum allowable speed of the rock?

At this maximum speed, what angle does the string make with the horizontal?

My Work:

I have successfully found the max speed to be 14 m/s (which is the correct answer) and I assumed that the angle it makes with the horizontal at the speed 14 m/s was zero since I used zero for theta to get the speed in the first place but it was incorrect.

I tried using 180 and 360 and a whole bunch of crazy unrelated thetha just for the heck of it and none of em seems to work.

Am I missing something big here?

Thanks

2007-10-27 20:27:04 · 4 answers · asked by Anonymous

A seagull, ascending straight upward at 6.4 m/s, drops a shell when it is 14 m above the ground.

(a) What is the magnitude and direction of the shell's acceleration just after it is released?


(b) Find the maximum height above the ground reached by the shell.

(c) How long does it take for the shell to return to a height of 14 m above the ground?

(d) What is the speed of the shell at this time?

2007-10-27 19:21:28 · 1 answers · asked by jaxmax50 2

leave the link where you found this answer please

2007-10-27 17:34:20 · 2 answers · asked by qtpie144life 2

Trying to figure this out: the sum of Weight + Normal force = MA ??? huh?

Also N-W = MA?

2007-10-27 17:33:58 · 4 answers · asked by Anonymous

A bicyclist is finishing his repair of a flat tire when a friend rides by at 3.4 m/s. Two seconds later, the bicyclist hops on his bike and accelerates at 2.6 m/s2 until he catches his friend.

2007-10-27 17:09:39 · 1 answers · asked by jaxmax50 2

I caught the tail end of a conversation on the World Series tonight and I was wondering the physics and maybe chemistry causing the differences in the way a ball would "break" at higher and lower altitudes.

2007-10-27 16:29:25 · 4 answers · asked by whoadi7767 2

A 540 gm rock is whirled on the end of a string 45 cm long which will break under a tension of 32 N.
a) What is the highest speed the rock can reach before the string breaks? (Neglect gravity.)

vmax = m/s
b) If two other strings identical to the first were attached to the rock, how fast could the rock be whirled before the three strings would break?

v'max = m/s
Next the rock is held by two of the same 45 cm strings with ends 63 cm apart and whirled in a circle between them. Neglect gravity.

c) What is the radius of the circle of motion?

R = cm
d) Now what is the maximum speed the rock can have before the string breaks?

v''max = m/s

2007-10-27 16:05:25 · 1 answers · asked by Anonymous

The figure shows two identical blocks tied together with a string which passes over a pulley at the crest of the inclined planes, one of which makes an angle q1 = 29° to the horizontal, the other makes the complementary angle q2 = 61°.
a) If there is no friction anywhere, with what acceleration do the blocks move?

a = m/s2
b) If each block has a mass m = 0.7 kg, what is the tension in the string while they are both moving?

T = N
c) Now suppose the coefficient of sliding friction between the blocks and planes is µ = 0.03. With what acceleration do the blocks move in this case?

af = m/s2

2007-10-27 16:04:37 · 1 answers · asked by Anonymous

A small block of mass m = 0.50 kg is fired with an initial speed of v0 = 4.5 m/s along a horizontal section of frictionless track, as shown in the top portion of Figure P7.58. The mass then moves along the frictionless semicircular, vertical tracks of radius R = 1.6 m.

(a) Determine the magnitude of the force exerted by the track on the block at points A and B.

track force at A? N

track force at B ? N

(b) The bottom of the track consists of a section (L = 0.40 m) with friction. Determine the coefficient of kinetic friction between the block and that portion of the bottom track if the block just makes it to point C on the first trip. [Hint: If the block just makes it to point C, the force of contact exerted by the track on the block at that point should be zero.]


here the figure...

http://img.photobucket.com/albums/v372/smilytwinkle/p7_58.jpg

i really need help on this...it so complicated...please help..thanks

2007-10-27 15:57:45 · 1 answers · asked by pinkepromise 2

2007-10-27 15:45:45 · 11 answers · asked by keyser soze 3

Some rooms are cooler or warmer than others due to heating or cooling. so what typically is room temperature?

2007-10-27 15:12:26 · 0 answers · asked by bekka 3

Ricardo, of mass 80 kg, and Carmelita, who is lighter, are enjoying Lake Merced at dusk in a 30 kg canoe. When the canoe is at rest in the placid water, they exchange seats, which are 3.0 cm apart and symmetrically located with respect to the canoe's center. Ricardo notices that the canoe moves 40 cm horizontally relative to a pier post during the exchange and calculates Carmelita's mass. What is it?

2007-10-27 15:06:16 · 3 answers · asked by Danyal Ali 1

I was wondering if you'd be able to help me with this. As of now, I only have a very, very basic understanding of physics. I took it in middle school and now I am being forced to take it again in high school.

This question relates to an assignment I was given in class that I do not understand. I do not expect you to solve this problem for me, but I would like to know if the formulas that I am using are correct, and if I am indeed going in the right direction, because, quite frankly, I can't understand half of the things my teacher says.

4π^2(L/T^2)= g

This is the equation we are dealing with. We're supposed to find what g is. L and T are variables we found by performing an experiment where we swung a pendulum. There are four separate numbers representing L (four lengths of the pendulum) and four numbers representing T that go along with each of the four Ls.

He told us to make two scatter plots, one with L along the y axis and T along the x axis, and one with L along the y axis and T^2 along the x axis. He then told us to draw lines to make them into graphs. He told me that the graph that went (T^2, L) should be a linear function and that the graph with the points (T, L) should be some kind of curved line. I don't know if this is true though, because he didn't seem to be paying attention when I asked him this...

Any way, to solve it via the analytical method, I plugged in an L and a corresponding T. I got an answer for g that was 9.04m/s^2. That doesn't sound right, but it doesn't sound horribly wrong, either.

To solve it via the graphical method, he told us we needed to find the slope of the line of the linear equation with the points (T^2, L). But thing is, I'm not sure where the slope comes into play when solving this problem. Does it replace the T^2 of 4π^2(L/T^2)= g or does it replace the whole L/T^2? Where does this variable go? I'm not sure exactly...I tried putting it in in the place of L/T^2, leaving me with 4π^2(slope)= g. The answer I got for putting it in was 11.05m/s^2. This is very different from the 9.04m/s^2 I got earlier, but it is the closest number that I was able to find...I adjusted the slope of me line multiple times using multiple methods but this was generally the result.

When doing this experiment, is it reasonable to find this kind of the difference in answers between the analytical and graphical methods? What do you think I am doing wrong?

2007-10-27 14:55:57 · 1 answers · asked by Anonymous

he figure shows two identical blocks tied together with a string which passes over a pulley at the crest of the inclined planes, one of which makes an angle q1 = 29° to the horizontal, the other makes the complementary angle q2 = 61°.
a) If there is no friction anywhere, with what acceleration do the blocks move?

a = m/s2
b) If each block has a mass m = 0.7 kg, what is the tension in the string while they are both moving?

T = N
c) Now suppose the coefficient of sliding friction between the blocks and planes is µ = 0.03. With what acceleration do the blocks move in this case?

af = m/s2

2007-10-27 14:52:55 · 1 answers · asked by GirlYgIRL 1

Block on Spring without Friction

A spring is stretched a distance of Dx = 40 cm beyond its relaxed length. Attached to the end of the spring is an block of mass m = 8 kg, which rests on a horizontal frictionless surface. A force of magnitude 40 N is required to hold the block at this position. The force is then removed.
a) When the spring again returns to its unstretched length, what is the speed of the attached object?

v0 = m/s

HELP: Apply the work energy theorem: KEfinal - KEinitial = Wspring.
HELP: What is the work done by the spring? How do we find it from the information given?
b) When the spring has returned only halfway (20 cm), what is the speed of the attached object?

v1/2 = m/s

2007-10-27 14:48:22 · 1 answers · asked by cuteeebabygirl 1

2007-10-27 14:39:58 · 9 answers · asked by Dzavid N 2

^_^

2007-10-27 14:34:43 · 2 answers · asked by Anonymous

if not then when is it?

2007-10-27 14:24:12 · 4 answers · asked by keightebby 2

2007-10-27 13:12:57 · 3 answers · asked by Anonymous

Guy throws football at 24m/s^2 at a 45 degree angle.It takes 3seconds to reach the top of its path.The ball is caught at same height that it was thrown. How long is it in the air?

2007-10-27 13:03:11 · 3 answers · asked by Anonymous