# Search results

1. ### Statics - Finding Reaction at Supports

Hey I'm just going over a past paper and I've lost the section of my notes RE this topic. I understand how to draw the free body diagram when there is a pin involved, but not when it is connected at 4 points, the fact that they're at an angle is not helping. Any help greatly appreciated...
2. ### Inertia of a pendulum with disc

A pendulum consists of a uniform thin rod of mass 5 kg and length 2 m to which is fixed a circular disc of mass 8 kg and radius 0.4 m. There is a pivot at one end. (a) Find the CoM and Moment of Inertia when the disc is: (i) half way along the rod; (ii) at the opposite end of the rod to the...
3. ### Hinged rod attached to elastic string

A rod (mass M, length L) hinged at point X. End Y is attached to X by an elastic string passing over a pin P, the natural length of the string is L. P is a distance L from X. Elastic Modulus of string: (1/4Mg) Refer to GPE to X and prove that total PE is: (1/4)MgL(1-cosθ-2sinθ) and find...
4. ### Horizontal Force in Pipe Bending

Homework Statement Water enters a pipe and goes through a bend with a contraction from 40mm to 25mm then into the atmosphere. What is the horizontal force required to hold the pipe in place? Homework Equations I have either been given the following or have calculated them using the standard...
5. ### Help solving a second order ODE with repeated roots, !

Thanks... I didn't think it would be that simple! I was going far too deep into this question. It's been a long night! haha
6. ### Help solving a second order ODE with repeated roots, !

Help solving a second order ODE with repeated roots, urgent! I have a differential equaition d2y/dx2 - 6dy/dx + 9y = 0 I have found the general solution to be y = (Ax + B)e3x Now I need to find the solutions to A and B so that... when y = 4, x = 0 when y = 49.e15, x = 5 I...
7. ### How do I Solve these two equations?

As part of a question on axial load I need to simplify two equations in terms of P ( and ). http://img207.imageshack.us/img207/5757/77260215.png [Broken] In the above you can see how FBA and FBC were simplified to 0.8081P and 0.7143P respectively. I understand both the section...
8. ### Solution of exact differential equation

Hi, I'm looking at a past paper for an exam I have on Tuesday and I'm struggling to understand this question on exact derivatives. Here is a link to the question: http://imageshack.us/photo/my-images/812/questiong.png/ I have looked over my notes for guidance and eventually turned to the...
9. ### Solving the Differential

I have been asked to solve the differential equation: cotan(x)\stackrel{dy}{dx} = y-1 ey2 Using substitution on the right hand side and by integrating tan(x) on the left hand side the answer I have got is: ln|sec(x)| = - 0.5 e-y2 + C Is the answer ok to leave in this form? It has...
10. ### Using the theory of simultaneous equations

Solved! Thanks for your help. I got a = 45, b = 30, c = 20, d = 5!
11. ### Using the theory of simultaneous equations

Homework Statement A, B, C and D are celebrating their joint birthdays and find that their ages add up to exactly 100 years. The sum of A's and D's ages equals the sum of B and C, while the di fference between the ages of A and D is twice C's age. Finally when D is as old as A is now, C...
12. ### Solving the Equation for a Complex Number

Thanks for the help, from what you've said I've gathered... From a2+b(b-4i)+8i-15=0 0=0+0i Therefore From a2+b(b-4i)+8i-15=0+0i a2-15=0 => a = \sqrt{15} b2-4b-8 = 0 b is solved with the quadratic? Is this correct so far?
13. ### Solving the Equation for a Complex Number

I have set the equation to = 0 but I don't understand how I can set to 0i though? I'm sure about the maths so far.
14. ### Solving the Equation for a Complex Number

Homework Statement Solve the equation \overline{y} (y - 2) = 2\overline{y} + 15 - 8i for complex number y Homework Equations \overline{y}y = a2 + b2 The Attempt at a Solution a2+b2+8i-4ib-15=0 a2+b(b-4i)+8i-15=0 Pretty clueless where to go from here? Or if I've even gone in...
15. ### Calculating the corresponding percentage

Homework Statement A car is travelling at initial speed 5.5ms-1. The car is on a decline of 8o. The brakes are used and the car stops after travelling 10m along the road (with no skidding). At the moment when kinetic energy is 51% lower than the initial value, ﬁnd the corresponding...
16. ### Calculate the mass of ice with heat transfer / latent heat

Oops, the Solid is placed on top of the ice. The ice then melts and the final temperature of both the solid and the ice is 10. So basically I'm looking for the initial mass of the ice, before the rock was placed onto it.
17. ### Calculate the mass of ice with heat transfer / latent heat

Homework Statement Find mi, the initial mass of ice. Ti = -20 ci = 2093Jkg-1K-1 Ts = +35 ms = 2kg cs = 837.4Jkg-1K-1 cw = 4187Jkg-1K-1 lf = 3.35x105Jkg-1 S = solid W = water I = ice lf = latent heat of fusion of ice / water Homework Equations Q=mc\DeltaT Q=C\DeltaT Q=ml The Attempt at a...
18. ### Questions on Energy changes on a ball

Thanks! KE = 1/2 mv2 (16-2) (2) = (0.25)v2 v = (sqrt)112ms-1
19. ### Questions on Energy changes on a ball

Hi, this is a question from a past paper, for which I have the exam on Monday. Please see the attachments. Solutions a) w = fx =(20)(1.5-0.7) =16J b)PE=mgh ^PE=(.25)(10)(1.5)-(.25)(10)(.7) PE=2J c) ? when i attempted a solution i used ^KE=^PE this gave me an answer of v^2=30 I...