# Search results

1. ### Normal distribution - Finding mean and standard deviation

Homework Statement A high jumper knows from experience that she can clear a height of at least 1.78m once in 5 attempts. She also knows that she can clear a height of at least 1.65m on 7 out of 10 attempts. Find to 3 dp the mean and standard deviation of the heights the jumper can reach...
2. ### Geometric Distribution Question

Homework Statement An experiment consistion of tossing three fair coins is performed repeatedly and "success" is when all three show a head. What is the probability that the success is on the third performance of the experiment? Homework Equations Geometric distribution equation p(x) =...
3. ### Differential Equation Uses

We did the basics of solving differential equations in Maths this week, well, it was actually just finding other approximate values of y for an equation given the derivative and a pair of co-ordinates on it. Are these for equations that cannot be subject to intergration? Also, what can...
4. ### Velocity of a proton question

Homework Statement Calculate the veolcity of a proton of energy 0.12 keV proton mass = 1.7 x 10^-27 Homework Equations The Attempt at a Solution I thought... 0.12 keV = 120 eV 120/1.60 x 10^-19 = 7.5 x 10^20 J E = 0.5mv^2 sqrt(2E/m) = v but I'm getting something to x 10^23 so its...
5. ### Roots of a cubic equation

I've been looking at some practise exams for the University I would like to apply to, I have to sit the exam on 4th November. We have never done finding the roots of a cubic equation before and I cannot figure it out from looking on the internet, the formulas are all horrible to understand...
6. ### Derivative of a sum of functions, also cubic graph roots

Derivative of a sum of functions What would you interperate this as? It is one of the subsections of Differentiation from the syllabus of a University entrance Exam in November but I cannot think what it is refering to. Differentiation: Derivative of xa, including for fractional...
7. ### RSA Algorithm Help

Struggling to put a number through this as I keep getting my original number as the encrypted number too. A = 11 p = 3 q = 5 n = pq = 15 z = (p-1)(q-1) = 2*4 = 8 k = co-prime of z = 7 So, A=11 n=15 z=8 (Public key) k=7(Public key) kj = 1 (mod z) 7j = 1 (mod 8) for which I am getting j =...
8. ### Maths Behind Credit Card Transactions

I am doing a qualification which requires me to chooses a subject for which I will research & produce a presentation & a 5000 word essay in December. As I plan to study maths at Degree Level I have decided to do a maths based project. My two basic ideas are.... How does Maths keep our...
9. ### Force on a surface

I was talking to my physics teacher the other day & he was saying about measuring the force exerted by an object on a surface if it is dropped onto it. The example we were using was dropping ball bearings onto a table (we are currently studying momentum) If I have got the above correct, what...
10. ### Shock absorber/Suspension advice (bike project)

After reading an article a few weeks ago about a man who had made a bicycle with a triangular & pentagonal wheel & started doing some reading on the shapes. Made a model of it but would like to try & make a full size one as we realised that it needs some parts that I couldnt make out of...