Yeah, we've been through this. Enough with the overanalyzing and "That's an impossible question" statements. It's just annoying, especially when the question can be answered and agreed upon the same by everyone.

What do you mean when you say the Earth like gravity is 10N? I don't think that's supposed to be measured in newtons.

lol.. hmm, I guess this question is unanswerable.. There is no real answer if g= 10N.. The question doesn't even make any sense..

.. just a very small taste of your own jackass medicine

Gravity is always measured in newtons in the UK? maybe the US is different?

gravity (g) is an acceleration, and is measured in m/s^2

Last time i studioed physics gravity was a force?

Weight = mass x gravity

So if i i have a mass of 8 N and gravity is 10 N then i have a weight of 80kg

Oh, 10 m/s^2. Thanks for pointing that out.

The strength of a classical gravitational field is measured in N kg ^ -1 (Newtons per kilogram). On the surface of the earth this is measured to be about 9.8 N kg ^ -1. Apologies if this has already been said in the thread, but I'm in an internet cafe so in a rush. If no one minds I'll set another question seeing as the last one apparently went a bit "stale":

An imaginary new HD video system (called Purple - Ray) has been launched and the laser it uses to read the disks has a wavelength of 400 nm (4 * 10 ^ -9 m). The lens used has a numerical appature of 1.5. What is the minimum size the markings on the disk (that represent the data) could have and still be resolved by the laser?

Note: numerical aperture is a dimensionless quantity, hence the lack of a unit.

Steven.

I've always known gravity to be measured in m/s^2. Of course the force of gravity could be 10N but that is completely dependent on the mass of the object that gravity acts on. If you use the equation F = (m1*m2*G)/(d^2) then G isn't measured in newtons or m/s^2. You get (Nm^2)/(kg^2). Unless I did something wrong.

Thats G, the universal Gravitational Constant ~ 6.673 x10^-11

An imaginary new HD video system (called Purple - Ray) has been launched and the laser it uses to read the disks has a wavelength of 400 nm (4 * 10 ^ -9 m). The lens used has a numerical appature of 1.5. What is the minimum size the markings on the disk (that represent the data) could have and still be resolved by the laser?

Note: numerical aperture is a dimensionless quantity, hence the lack of a unit.

Steven.

its not .002 meters is it?
sorry, I don't have much experience with optics..

Hi Josh. In fact, I didn't even state the question right. 400 nm is of course 4 * 10 -7 m. Evsn so, the answer is still far smaller, being 600 nm (6 * 10 -7 m). The resolution is given by laser wavelength / numerical aperture. This is actually somthing that came up during my final year project at uni, 'cause I was building a two photon microscope. Anyway, do you have another question?

Steven.