TodayIsGift

圖片參考：http://imgcld.yimg.com/8/n/HA01132001/o/2013041522...

I want to ask how can we find the north and south pole of the solenoids?

Is it by right hand rule? Thanks so much!!!

圖片參考：http://imgcld.yimg.com/8/n/HA01132001/o/2013041317...

I want to ask is this two cis- and trans- wrong? Since the CH3 is on the same side but it is trans, the CH3 is on different sides but it's cis-, please help me~~~~

圖片參考：http://imgcld.yimg.com/8/n/HA01132001/o/2013040322...

I want to ask under this condition, the total current decreases so the current passes through the bulb decreases.

At the same time, due to internal resistance, voltage across light bulb increases.

The answer said the bulb becomes brighter.

However I don't understand since the current decreases and voltage increases, how do we know the bulb becomes brighter?

Thanks for your help!!!!!!!!!!!!!!!!!!!!! >O<

圖片參考：http://imgcld.yimg.com/8/n/HA01132001/o/2013040214...

I want to ask should we write 1-bromo-2,3-dichloropropane or

3-bromo-1,2-dirchloropropane? Why? Thanks a lot!

圖片參考：http://imgcld.yimg.com/8/n/HA01132001/o/2013040121...

Please draw the circuit diagrams for the above four pictures!!!

圖片參考：http://imgcld.yimg.com/8/n/HA01132001/o/2013040121...

And please answer this question, thanks a million!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

I would like to ask question 25 (d). We have to caculate the molarity of zinc chloride formed. We know the no. of moles of it, but how can we know the volume of it? As we have to know both the no. of moles and the volume to caculate the molarity. Please help~~~~~Many thx~~~~

圖片參考：http://imgcld.yimg.com/8/n/HA01132001/o/2013020120...

圖片參考：http://imgcld.yimg.com/8/n/HA01132001/o/2013020120...

I would like to ask question 25 (d). We have to caculate the molarity of zinc chloride formed. We know the no. of moles of it, but how can we know the volume of it? As we have to know both the no. of moles and the volume to caculate the molarity. Please help~~~~~Many thx~~~~

我想問probability幾時要係個分數乘個整數呢？例如呢條數:

Stem(tens) Leaf(units)

1 2 5 5 7 8

2 4 4 4 4 5 6 7 9

3 2 2 2 2 5 5 5 6 8

4 2 3

Find the probability that the mean score of the two students is the same as the mean score of the 24 students. (mean score is 28)

Ans: Let x and y be their marks.

(x+y)/2=28

x+y=56

Possible combinations: (18,38) (24,32), (27,29)

Probability:

2x(1/24x1/23)+2x (4/24x4/23)+2x (1/24x1/23)

=3/46

為什麼要在分數之前乘一個整數2 呢？

我想問為何香港不可禁止售煙？

Please solve question 21 cii) Thanks a lot!!

圖片參考：http://imgcld.yimg.com/8/n/HA01132001/o/7012072200...

Question 22 part c:

圖片參考：http://imgcld.yimg.com/8/n/HA01132001/o/7012072000...

Question 25 and 26(part dii):

圖片參考：http://imgcld.yimg.com/8/n/HA01132001/o/7012072000...

Please solve it~thx

圖片參考：http://imgcld.yimg.com/8/n/HA01132001/o/7012061800...

Please solve it~thx

First question:

Three girls A, B and C run at steady speeds from point X to point Y along different paths as shown. They take the same amount of time to complete the journey.

圖片參考：http://imgcld.yimg.com/8/n/HA01132001/o/7012061700...

Is the following statement correct?

Girl A has the highest speed.

Second question:

Is the following statement correct?

An object moving at a constant speed must have zero acceleration.

Third question:

Force F is the resultant force of a 2N force and a 5N force. Which of the following is the possible magnitude of F?

(1) 2N

(2) 3N

(3) 5N

The following is the question:

圖片參考：http://imgcld.yimg.com/8/n/HA01132001/o/7012061500...

a) the worker pulls the string such that the box accelerates upwards with

a constant acceleration of 0.5 m/s. Find the force acted by the man on the ground,

Ans:Let the normal force acting on the worker by the ground R and the tension in the string be T.

Consider the motion of the box.

T- mg = ma

T= 20x0.5 + 20x9.81 =206N

Consider the worker,

T+R=Mg

R=Mg -T = 70x9.81 - 206=481N

By the Newton's third law, the force acted by the man on the ground is also 481N.

I don't understand why T+R=Mg, but not R-T=Mg since T should be in the

same direction as Mg.

圖片參考：http://imgcld.yimg.com/8/n/HA01132001/o/7012061300...

Please answer it~

The following is an MC question.

If 0<_x<_360, solve (cos x -3)(3sin x -2)=0, corr. to 3.s.f

A. 0.730 or 1.23

B.0.730 or 2.41

C.0.730 or 3.87

I cannot solve this question. Please help me to solve this problem, thank you so much!

=) @v@_____________________________________________________

_____________________________________________________________

______________________________________________________________

_______________________________________________________

我想問下點解burette同pipette既concentration就重要，

而conical flask的就不重要？

如果個standard solution係burette入面，可以理解如

果個burette入面既solution被dilute左，兩個solution既molarity都唔知，

就計唔到，但係如果個standard solution係conical flask入面，

conical flask既concentration不也重要嗎？如果唔係就會兩個

solution既molarity 都唔知。

The manager of a factory proposes to increase the salaries of the workers by 10% next year and then a further 20% the following year. THe workers give a counter proposal. They want their salaries to increase by 20% next year and then by 10% the following year. Would the manager accept it?

Please answer the question, thx!

Please solve this problem, thx~=)

A ball of mass m is thrown vertically downwards from height H with speed v. The ball rebounds and reaches the maximum height of H. Is the following statement correct? Why?

-During the collision, the ball loses 1/2mv^2 of energy.

I would like to ask what is a "metal-metal ion system"? Please answer in English. Thank you so much.