Q4+q10 2004 Hsc (1 Viewer)

[spank_meh]

umm would any1 be so kinds and explain q4 and 10 from 2004 hsc? i have the answers but i dun really get the whole answer thing :S

4. An object of rest mass 8.o kg moves at a speed of .6c relative to an observer. What is the observed mass of the object?
Answer is B... when it gives the answer it goes 8 over root [1-.6 squared over 2 squared]

were on earth does the two come from? shouldnt it be just the .6 squared???

10. i dont really have the diagram sorry.. im sure you all have the question... argh why is the answer A???

thnx

 

[Captain Gh3y]

umm would any1 be so kinds and explain q4 and 10 from 2004 hsc? i have the answers but i dun really get the whole answer thing :S

4. An object of rest mass 8.o kg moves at a speed of .6c relative to an observer. What is the observed mass of the object?
Answer is B... when it gives the answer it goes 8 over root [1-.6 squared over 2 squared]

were on earth does the two come from? shouldnt it be just the .6 squared???

10. i dont really have the diagram sorry.. im sure you all have the question... argh why is the answer A???

thnx

Q4:
From your formula sheet, the Mass Dilation Formula:
m_v = m_o/√(1-v²/c²)
m_v = 8/√(1-.6²)
m_v= 10kg (by calculator)
This is the answer B.
That 2 is a typo, they still got the right answer.

Q10. You can see that (D) and (C) are wrong straight away, because current, field and force are always perpendicular to each other, so the field can't be parallel to the force. (I should mention this is with your right hand).
Now test (A): If field is vertically upwards, and current is from X to Y, point your thumb from X to Y (conventional current), and your fingers vertically upwards.
Your palm will be pushing into the page, as shown by the big arrow.
Another possibility is that the field is vertically down and current moves from Y to X, but that's not an option.

 

[spank_meh]

Q4:
From your formula sheet, the Mass Dilation Formula:
m_v = m_o/√(1-v²/c²)
m_v = 8/√(1-.6²)
m_v= 10kg (by calculator)
This is the answer B.
That 2 is a typo, they still got the right answer.

Q10. You can see that (D) and (C) are wrong straight away, because current, field and force are always perpendicular to each other, so the field can't be parallel to the force. (I should mention this is with your right hand).
Now test (A): If field is vertically upwards, and current is from X to Y, point your thumb from X to Y (conventional current), and your fingers vertically upwards.
Your palm will be pushing into the page, as shown by the big arrow.
Another possibility is that the field is vertically down and current moves from Y to X, but that's not an option.

thank u sooo much i think i get Q10 now

even tho i use a different rule i use fingers for the direction of the current palm as the direction of the field nd thumb as the direction of the force
i dno it works the same but

thank u