# Search results

1. ### Resistivity - Need definition

I am revising for my A levels and I have noticed that a common question on the paper is to define RESISTIVITY. I have looked and looked but found no definitive description or a good definition. I know the formula but is it right to just say that "resistivity is directly proportional to a...
2. ### Force in circular motion

Just wondering if anyone can check over my answer for a question. Q) A 1.7kg object is swung on the end of a 0.6m string in a vertical circle. The object does one revolution every 1.1s. What is the tension in the string at the top of the circle? and the bottom? A) m=1.79kg r=0.6m...
3. ### Geometric progression

just a check of my work please. I have to write an expression for the nth term of this geometric sequence. a1=100 a2=106 a3=112.36 I've worked out the ratio to be r=1.06 I am using the formula un=ar(n-1) so the expression i have come up with is un=100(1.06)(n-1) Is this correct? I have...
4. ### Series and sequence

sorry i made a mistake in the question part, it is supposed to read u1=-1
5. ### Series and sequence

Just a check of my work please, The topic is series and sequence, Question: The sequence u1, u2, u3,..... where u1 is defined by u1=2 and Un+1 =un+4 Find the nth term, un, of the sequence. I got the answer, u1=-1 u2=-1+4= 3 u3= 3+4 = 7 So: un = 4(n-1)-1 This seems to work but not sure if...
6. ### Calculate the Current, Lost Volt and P.d across parallel resistors?

I'm pretty sure the lost volt is the resistance inside the battery. Once you work out the lost volt you can minus that from the voltage of the battery and work out the real value of V. Most questions dont include thw lost volt because it is quite small and considered negible. I think they are...
7. ### Displacemnet along a spring

hi thanks that kinda makes sense, im just having trouble with the amplitude...x0...how do i work this out and fit it in?
8. ### Amplitude of a wave

Hi, does anyone know how to calculate the amplitude of a wave knowing the frequency and wavelength
9. ### Displacemnet along a spring

i got 0.2m for the wavelength but am not sure how to use this in the equation would it be -0.2cos5t ?
10. ### Displacemnet along a spring

Hi guys, Having trouble with a question I need to know the displacment of a point on a spring at certain times. At t=0 point p is at its maximum displacement at 2cm point A is further down the spring at p-A = 0.4m A transverse wave of frequency 5Hz is moving along the spring at...
11. ### Simultaneous polynominals

i thought i was just to put the factor into the equation. Not sure what other way to do. Is the second part correct?
12. ### Simultaneous polynominals

simultaneous polynominals!! stuck on this coursework question The cubic polynominal f(x)= 4x^3+ax^2+bx+6 has a factor (x-2) when it is divided by (x+1) it has a remainder 0f -15 find the values of a and b I did as follows factor (x-2) f(-2) 4(-2)^3+a(-2)^2+b(-2)+6=0 equals 4a-2b=26...
13. ### Drawing graph of function

I have been asked to draw the graph of the function f(x)= (x+3)/(x-2) I have found where it cuts the y axis by putting x=0 but am unsure of how to find the x value. I found the inverse of f(x)= (x+3)/(x-2) which gave me x= (y+3)/(y-2) then set y=0 which again gave me x=-3 I have checked...
14. ### Composite functions

ahhh yer that makes sense :) thanks
15. ### Composite functions

is it because g is a gunction of x, not x itself!? am i doing it correctly then? :)
16. ### Composite functions

Im looking for g(f(5)) where f(x) = X^2 - 3x and g(x) = 8 + 2x - x^2 xER and x is greater than or equal to 1 I have first found f(5) (5)^2-3(5) which equals 10 However when i do g(10) 8+2(10)-(10)^2 that gives me a negative number of -72!! Which cant be...
17. ### Inverse Functions

I can now thanks :) I see what you have done but im not sure why 1/x becomes 2/x in this circumstance. Im just trying to understand the mechanics behind it so i can be fully aware. If h(x) was 1/x + 5 would it still be 2/x +5 or 2/x + 10? your correct in your assumption, my teacher is poor...
18. ### Inverse Functions

Just want to check that i am doing this question correctly. f(x) = 2x+5 h(x) = 1/x , x \neq0 Find the inverse of fh(x) So first i found the function fh(x) 2*1/x+5 then let y = 2*1/x+5 , x \neq0 now this is the bit i cant rememeber how to do, when i try and make...
19. ### Motion in a straight line tough one

sorry yer got 12 now, me calculating wrong lol couldnt i use T and work iit out algebraically in an equation?

21. ### Motion in a straight line tough one

6s*9ms^-1 = 54m 108m-54m = 54m v^2=u^2+2as 0^2=9ms^-1 + 2a*54 a = -0.84359.....ms^-2 t=v-u/a t=0ms^-1/0.8435...ms^-2 t = 10.7s total time = 6 + 10.7 = 16.7s
22. ### Motion in a straight line tough one

The question actually says 2 cyclists (B) travelling at 9ms^-1 and (A) travelling at 10ms^-1 are at the same point when they see traffic lights 108m away. B travels at its speed for a furthe 6seconds before decelerating and stopping at the lights. A travels for a time T before decelerating and...
23. ### Motion in a straight line tough one

motion in a straight line....tough one ok, a cyclist is travelling at 10ms^-1. he sees trafic lights ahead at 108m. He carries on cycling for a time T before decelerating and stopping at the lights 16.7seconds after he first saw the lights. Calculate T Im a bit stuck because i feel this...

ah yer that makes more sense, 15m/45m/s = 0.3333333 s

Homework Statement ok the question is as follows. A pilot flying at 45m/s is trying to bomb a target on the ground 15m in diameter. he is at a height of 98m (a)how long does it tke for the bomb to hit the ground? (b)at what horizontal distance does the pilot have to be to release the bomb...
26. ### Intial speed of projectile motion from height

ok im trying to find out how to work out the intial velocity of a projectile dropped from a height h and reaches a distance s. say a ball thrown from a height of 2.8 metres and reaches a distance of 3 metres. I want to be able to work it out WITHOUT having to work out the time. so cant...
27. ### Path of positivley charged particle in electric field

what do i need to do to work that our RoyalCat? it is a magnetic field
28. ### Path of positivley charged particle in electric field

the choices i have are a) the particle stays on the same path, b)the particle follows a circular path in an anticlockwise direction c)the particle follows a circular path in a clockwise direction d)the particle the particle follows a helical path in an anticlockwise direction e)the particle...
29. ### Simple circuit

so am i right in believing it to be bulb p? the one on its own but in parallel with the others
30. ### Path of positivley charged particle in electric field

sorry i didnt mean the grip rule just the right hand rule. i checked it again and figured that if the particle was travelling along the +x axis and the electric field was in the -y direction...the force on the particle would be giong into the page(so to speak) this would make it travel in an...