# Search results

1. ### Significant figures ?

zero in the middle of non-zero numbers is always counted as a sigfig but if it's the last number.. then it may or may not be counted as sigfig if it's the first one, it is not a sigfig (e.g 0.0002 --> 1 sigfig)
2. ### Density of sodium hydroxide

i thought it was w/w.. and i couldn't find the density of NaOH 20% solution It makes more sense if it is w/v... Thanks a lot!!
3. ### Density of sodium hydroxide

Hi all.. I have a question regarding the density of a solution. In my lab manual, it said to use 50 mL of 20% NaOH solution I have problem of understanding whether the 20% is the molar or mass or volume basis.. It doesn't state anything else in there.. what does it usually means? And i think...
4. ### Need some help regarding a density question

I think you should use the concept of Buoyancy Force to solve it.. Balance the buoyancy force and the total weight to get the volume of the balloon and payload, then substract the volume of payload..
5. ### Don't understand by the arrangement of the capacitors in the diagram.

what do u mean by separated? by this, do you mean the source is one 6.0 V battery? or each battery is 6.0 V? well.. just take these 2 batteries and consider it as one with voltage equal to the sum of the voltage of the two batteries. Say, the voltage of each battery is 6.0 V, then the...
6. ### Isothermal Expansion

Vi = Vi Vf = 3 Vi since it expands three times its initial volume
7. ### Spectral bandpass

thank you so much! :smile:
8. ### Spectral bandpass

Hi.. can anyone please explain to me what does it mean by spectral bandpass of monochromator? i tried to look for it in my textbook, but i can't really find anything.. what i think is that this spectral bandpass gives you the size (wavelength range) of the wave component (after it passed the...
9. ### Help on friction and motion

sum of all external forces = mass x acceleration, so if sum of external forces = 0, then acceleration must be 0 acceleration = 0 doesn't mean it will stop.. but acceleration < 0 (i.e. decceleration) will slow it down until it stops in Newton's first law: An object at rest tends to stay...
10. ### M - (x -n)^2 = ?

well about the book 5 + 4x - x^2 = M - x^2 + 2nx - n^2 and then add x^2 to both sides of equation, 5 + 4x = M + 2nx - n^2 by comparing coefficients, it means that in order to make this equation valid, you have to have the same coefficient in left hand side and right hand side for x^1, and...
11. ### M - (x -n)^2 = ?

4x - x^2 + x^2 - 2nx = m - 5 - n^2 4x + (- x^2 + x^2) - 2nx = m - 5 - n^2 since -x^2 + x^2 = 0 then 4x + 0 - 2nx = m - 5 - n^2 4x - 2nx = m - 5 - n^2 x(4 - 2n) = m - 5 - n^2 since there are no x on the right hand side of this equation, then 4 - 2n must be equal to zero for this...