# Search results

1. ### Finding the Directionality of a Sound

But the sounds are going in different directions, my professor said you can't treat sounds like forces and take a resultant. He said that I had to use the directionality index but I don't know how to apply that. I used Lp = Lw - 20log(r) - 11 - Ae with the only unknown being Lw, solved for...
2. ### Finding the Directionality of a Sound

I recently performed a noise lab and I am required to write a program to find the room constant of the room where the data was collected. Basically I would be using the formula: Lp = Lw + 10log(Q/[4*pi*r^2] + 4/R) Where Lp is the sound pressure level which was collected during the...
3. ### Mass Balance of Biomass Question

The Problem: Bio fuels are receiving more and more attention. For biomass waste materials (cellulose, manure etc.), the first step in the process is typically to convert the biomass to sugar (glucose, C6H12O6). This first step is only able to produce 0.1 g glucose per g of biomass. The...
4. ### Find the Differential Equation Relating Input Voltage and Output Voltage

While I'm at it, I'm having trouble with another question like the one above, but this time it's a mechanical system. It's the jpeg below. I started off with the writing equations for each mass Mass 1: K1x1 + DB(x) + k2(x1-x2) = 0 Mass 2: m2D^2x = DB(x1-x2) + k2(x1-x2) First off...
5. ### Find the Differential Equation Relating Input Voltage and Output Voltage

Ohhhh okay that makes sense. Took a while to wrap my head around it but I got the right answer in the end. Thanks! :)
6. ### Find the Differential Equation Relating Input Voltage and Output Voltage

Hey all, I'm stuck on a dynamic systems question, it's attached as a jpeg I started off by writing nodal equations for each node: Node 1: 1/R1(ei-eA)=C1D(eA-eo)+1/R2(eA-eB) Node 2:1/R2(eA-eB)=C2D(eB) I know that I have to isolate for ei and eo but I'm really confused with...
7. ### Using Stress/Strain Curve to Find Yield Strength and Modulus of Elasticity

Awesome, thanks! :)
8. ### Using Stress/Strain Curve to Find Yield Strength and Modulus of Elasticity

So then...the slope of the linear portion of the curve?
9. ### Using Stress/Strain Curve to Find Yield Strength and Modulus of Elasticity

Hey guys, I recently did a compression lab with different materials (wood and pvc pipe) and I have to plot the stress/strain curves given the data collected, as well as find yield strength (0.2% offset), ultimate compressive strength, and modulus of elasticity. I've already calculated...
10. ### Writing Nodal Equations for a Thermal System

Sorry I was going off of my professors notes for a different system and he used P. Would this be correct if I was looking at specifically at the node Ti? 0=-1/R1(Ti-T1)-1/R5(Ti-To)-Ci(Q(t)-Ti) What I understood from nodal analysis is that you start at one node and look at what's going in...
11. ### Writing Nodal Equations for a Thermal System

So I have to write out nodal equations for a system that I was given, and I started off by drawing out the flow diagram to see where everything was. I'm having trouble starting the nodal equations though. The attachment has 2 diagrams: figure 1 is the correct diagram that models the thermal...
12. ### Need help with Laplace's Equation

Homework Statement Determine whether each of the following functions is a solution of Laplace’s equation uxx + uyy = 0. x^3 + 3xy^2 ux=3x^2 uxx=6x uy=6xy^2 uyy=6x 6x+6x=12x and is therefore not a solution Did I do that right? I'm just learning about this topic and it's...
13. ### Finding a Limit Using L'Hopital's Rule

Oh okay I understand that. Thanks! I think I've got the right answer now
14. ### Finding a Limit Using L'Hopital's Rule

Homework Statement lim x→∞ of ((x^3+2x-∏)^(1/3))-x Homework Equations L'Hopital's Rule: If it is an indeterminate form, take the derivative of the top and bottom until you do not get an indeterminate form anymore. The Attempt at a Solution lim x→∞ of ((x^3+2x-∏)^(1/3))-x...
15. ### Using a Riemman Sum to find the area under a curve (n intervals, left endpoint)

Hello, I'm having a bit of trouble calculating the area under the curve of x^2 on the interval x=-3 to x=1. The question says that there I have to use n subintervals and left endpoints. Relevant Equations Δx=b-a/n xi=a+(Δx)(i-1) -its i-1 because we're using a left endpoint, otherwise...
16. ### Finding the best interval of solutions for N (using epsilon)

The problem is: lim as x→- ∞ (-5x/x-2)=-5 And I have to find the best interval of solutions for N Relevant equations: if x>N then |(-5x/x-2)-(-5)|<ε My attempt: |(-5x/x-2) - (-5)|<ε |-10/x-2|<ε x-2< 10/ε as x→-∞ we can assume that x-2<0 x-2<10/ε x< (10/ε)+2...
17. ### Altitude of a Rocket Launched into Space

Oh alright that makes sense. Thank you!
18. ### Altitude of a Rocket Launched into Space

The Problem: A 4.60 kg rocket is launched directly upward from Earth at 9.00 km/s What altitude above the Earth's surface does the rocket reach? Relevant Equations: v = √ (2GM/r) The Attempt: m = 4.60 kg v = 9km/s = 9000m/s G = 6.67 x 10^-11 9000^2 = 2(6.67^-11)(4.60)/r...
19. ### Force Constant of Surgical Tubing

Oh okay I understand. So then I have to re evaluate the force constant. When I found the force constant the first time it was surprisingly constant. For example, for every 50 grams added to the end of the tube it stretched 0.5 cm. Thanks for the help! Hopefully the new length of...
20. ### Force Constant of Surgical Tubing

The Problem: I found the force constant of surgical tubing for a catapult I have to make for physics class. However I discovered that I have to reduce the length of the tubing a few centimetres to get a longer range for the projectile. Will reducing the length change the force constant...
21. ### How To Calculate Catapult Trajectory

Haha okay this makes much more sense now. It funny cause I actually did an investigation on Hooke's Law a couple weeks ago doing what both of you guys said to find the constant of a spring, but I totally forgot about it. Thank you guys so much!
22. ### How To Calculate Catapult Trajectory

Hey thanks for the reply, Yeah I figured just experimenting would be the best route to take. How would I know the value of k of the spring though? If I go to a store and buy a spring would it say what the stiffness is? Or could I just use the spring scale to measure the force of the...
23. ### How To Calculate Catapult Trajectory

I have an assignment where I have to build a catapult that is able to launch a bean bag any distance between 8-12 metres. My teacher will give me a random distance on the day it's due, and I have to be able to adjust the catapult in order for it to launch that distance. I'm having a bit of a...