Physics: Post your doubts here!

[princess Anu]

can someone please show me the solution for this.

 

[princess Anu]

How to do this. HELP!!!!!!

Q: A conical pendulum consists of a small massive bob hung from a light string of length 1m and rotating in a horizontal circle of radius 30cm. Deduce the speed for rotation in revolutiona per minute.

 

[Copy Cat]

Last part?

 

[Copy Cat]

Last Part

 

[nehaoscar]

Both inverting and non-inverting amplifiers work on negative feedback where part of the output is fed back to the inverting terminal.
Does that mean in both type of amplifiers, the gain is reduced?

 

[Usama waheed3]

Aslam w.a.a hello there, can anybody help me i want to ask that i got in physics C grade in AS level exam and i calculated my marks and compared with grade threshold and so i according to that am getting B grade so what should i do now to improve my grade any help

 

[holoholo]

explanation for question 6 please
http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_s04_qp_4.pdf

 

[sharukh45]

HOW TO SOLVE THIS QUESTION CAN ANY ONE HELP PLZ

 

[sharukh45]

hello gys can any one explain this

 

[sharukh45]

see solution 983 at
http://physics-ref.blogspot.com/2015/09/physics-9702-doubts-help-page-203.html

thank you broo

 

[Rizwan Javed]

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.

 

[nehaoscar]

hello gys can any one explain this

Solution 784
http://physics-ref.blogspot.in/2015/05/physics-9702-doubts-help-page-158.html

 

[a_wiserME!!]

can someone pls explain this .. i keep doing and i get the answer as 4.3 but the ms says 3.4
TIA

 

[Mr.Physics]

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

Vertical v at t=0 is 6ms^-1

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

 

[Rizwan Javed]

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

Look, from the graph, at t=o, the vertical component of the ball's velocity is 5.9 ms^-1.



^ 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.

 

[a_wiserME!!]

Look, from the graph, at t=o, the vertical component of the ball's velocity is 5.9 ms^-1.

View attachment 58664

^ 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.

see solution 527 at
http://physics-ref.blogspot.com/2015/04/physics-9702-doubts-help-page-102.html

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!

 

[Mr.Physics]

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!

Yeah you must make sure that it's in degrees

 

[HumptyR]

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

 

[My Name]

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

 

[HumptyR]

View attachment 58709

Thanks! That was fast again. Flash