explanation for question 6 please
http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_s04_qp_4.pdf
http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_s04_qp_4.pdf
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Physics: Post your doubts here!
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thank you broo
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As you know that feather is falling in a vaccum, so there'll be no air resistance.
The initial velocity will be equal to 0 as it falls from rest. The time taken to fall the distance 'L' is T.
So substitute this given info in to the equation of motion:
s= ut+0.5at^2
L = 0.5a(T^2)
make a the subject.
a = 2L/T^2 ----- equ (1)
Now we're asked what distance it woul cover in 0.5T. So again substitute the values in the equation of motion but this time using t=0.5T
so,
new distance = ut +0.5at^2
= (0)(0.5T) + 0.5a((0.5T)^2) ---- equ(2)
substitute a = 2L/T^2 from equ (1) into equ (2):
new distance = 0.5(2L/T^2)((0.5T)^2)
solving it would give :
new distance = 0.25L
So B is the answer.
The initial velocity will be equal to 0 as it falls from rest. The time taken to fall the distance 'L' is T.
So substitute this given info in to the equation of motion:
s= ut+0.5at^2
L = 0.5a(T^2)
make a the subject.
a = 2L/T^2 ----- equ (1)
Now we're asked what distance it woul cover in 0.5T. So again substitute the values in the equation of motion but this time using t=0.5T
so,
new distance = ut +0.5at^2
= (0)(0.5T) + 0.5a((0.5T)^2) ---- equ(2)
substitute a = 2L/T^2 from equ (1) into equ (2):
new distance = 0.5(2L/T^2)((0.5T)^2)
solving it would give :
new distance = 0.25L
So B is the answer.
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can someone pls explain this .. i keep doing and i get the answer as 4.3 but the ms says 3.4
TIA
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Vertical v at t=0 is 6ms^-1View attachment 58660
View attachment 58661
View attachment 58662
View attachment 58663
can someone pls explain this .. i keep doing and i get the answer as 4.3 but the ms says 3.4
TIA
First, find v using this info
sin60= vert. v / v
v = 6/sin60 = 6.928 ms^-1
Now use v to find hor.v
cos60 = hor. v/ v
Hor.v = cos60 x 6.928 = 3.46 ms^-1
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Look, from the graph, at t=o, the vertical component of the ball's velocity is 5.9 ms^-1.View attachment 58660
View attachment 58661
View attachment 58662
View attachment 58663
can someone pls explain this .. i keep doing and i get the answer as 4.3 but the ms says 3.4
TIA
^ so we're given this info, that i've drawn on the figure.
For finding Vh, apply tan
tan 60° = 5.9/vh
vh = 5.9 / tan 60°
vh = 3.4 ms^-1 Ans.
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thanx ... i just realised what i had done....i was doing the same calculation but my calculator was in a different mode ..
soo sorry for the trouble!
Last edited:
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Yeah you must make sure that it's in degreesthanx ... i just realised what i had done....i was doing the same calculation but my calculator was in a different mode ..
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An experiment is carried out to measure the resistance of a wire. The current in the wire is (1.0 ± 0.2)A and the potential difference across the wire is (8.0 ± 0.4)V. What is the resistance of the wire and its uncertainty?
A (8.0 ± 0.2)Ω
B (8.0 ± 0.6)Ω
C (8 ± 1)Ω
D (8 ± 2)Ω
A (8.0 ± 0.2)Ω
B (8.0 ± 0.6)Ω
C (8 ± 1)Ω
D (8 ± 2)Ω
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Thanks! That was fast again.
Flash
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The Young modulus of the material of a wire is to be found. The Young modulus E is given by the equation below.
E=4F*l/πd^2*x
The wire is extended by a known force and the following measurements are made. Which measurement has the largest effect on the uncertainty in the value of the calculated Young modulus?
E=4F*l/πd^2*x
The wire is extended by a known force and the following measurements are made. Which measurement has the largest effect on the uncertainty in the value of the calculated Young modulus?
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Oh! am IWelcome.
No,it wasn't.
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A weight W hangs from a trolley that runs along a rail. The trolley moves horizontally through a distance p and simultaneously raises the weight through a height q.
As a result, the weight moves through a distance r from X to Y. It starts and finishes at rest. How much work is done on the weight during this process?
A Wp
B W(p + q)
C Wq
D Wr
As a result, the weight moves through a distance r from X to Y. It starts and finishes at rest. How much work is done on the weight during this process?
A Wp
B W(p + q)
C Wq
D Wr
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It's C, because work done = Force applied * distance moved in the direction of force
In this case the force acting on the mass is the tension in the string holding the mass which is equal to the weight in this case. And the distance moved by the weight in direction of this force is q.
So,
work done = W *q
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it's the diameter which has the largest effect. Look in the equation, d is a squared quantity. So the %age uncertainty in d would need to be doubled. So it will have the largest effect.