- #1
Dependent motion problem with ropes
- Thread starter theBEAST
- Start date
-
- Tags
- Motion
AI Thread Summary
The discussion revolves around solving a dependent motion problem involving ropes, where the user is struggling with two unknowns, A and C, and is unsure how to eliminate B from their equations. Participants suggest focusing on the dependencies between length changes and recommend rearranging the equation L = SA - SB + 2SC to isolate SA. They clarify that taking the derivative will help eliminate constants like SB and L, simplifying the problem. The conversation emphasizes the importance of understanding calculus concepts, particularly derivatives, in resolving the issue. Ultimately, the user gains clarity on how to approach their problem.
- #2
gneill
Mentor
- 20,989
- 2,934
theBEAST said:
What are your two unknowns? Remember, you're looking for dependencies between certain length changes.
- #3
theBEAST
- 361
- 0
gneill said:
I know it's A and C but I don't know how to get rid of B :S
- #4
gneill
Mentor
- 20,989
- 2,934
theBEAST said:
Here's your drawing with the distances labeled.
Your equation is:
L = SA - SB + 2SC
What you're looking for is the rate of change of SA with respect to a rate of change of SC. So rearrange your formula to have SA on the left and the rest on the right. Now, are you familiar with calculus (derivatives)?
Attachments
- #5
theBEAST
- 361
- 0
gneill said:Here's your drawing with the distances labeled.
Your equation is:
L = SA - SB + 2SC
What you're looking for is the rate of change of SA with respect to a rate of change of SC. So rearrange your formula to have SA on the left and the rest on the right. Now, are you familiar with calculus (derivatives)?
Oh... I see, so if you take the derivative Sb and L are eliminated since they are constant?
- #6
gneill
Mentor
- 20,989
- 2,934
theBEAST said:
Yup.
Neglect gravity other than that of water; neglect friction.
F1=ρgsh=1000*10*1*(1+4)=50000 N;
F1=ρgsh=1000*10*0.1*4=4000 N;
F3=50000-4000=46000 N?
Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system
$$M(t) = M_{C} + m(t)$$
$$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$
$$P_i = Mv + u \, dm$$
$$P_f = (M + dm)(v + dv)$$
$$\Delta P = M \, dv + (v - u) \, dm$$
$$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$
$$F = u \frac{dm}{dt} = \rho A u^2$$
from conservation of momentum , the cannon recoils with the same force which it applies.
$$\quad \frac{dm}{dt}...
I was told forces are vectors so they can be divided into x and y components, but what about the normal force or the force of static friction? do you divide those into x and y components if say you had a block that was lying on an angled surface?
Similar threads
Hot Threads
-
Torque biomechanics
- Started by Naucus
- Replies: 6
- Introductory Physics Homework Help
-
Work Done in slowly pulling a thread
- Started by Bling Fizikst
- Replies: 28
- Introductory Physics Homework Help
-
How do you calculate the pull of this piston?
- Started by vdance
- Replies: 27
- Introductory Physics Homework Help
Recent Insights
-
Insights Quantum Entanglement is a Kinematic Fact, not a Dynamical Effect
- Started by Greg Bernhardt
- Replies: 11
- Quantum Physics
-
Insights What Exactly is Dirac’s Delta Function? - Insight
- Started by Greg Bernhardt
- Replies: 5
- General Math
-
Insights Relativator (Circular Slide-Rule): Simulated with Desmos - Insight
- Started by Greg Bernhardt
- Replies: 1
- Special and General Relativity
-
Insights Fixing Things Which Can Go Wrong With Complex Numbers
- Started by PAllen
- Replies: 11
- General Math
-
Insights Fermat's Last Theorem
- Started by fresh_42
- Replies: 105
- General Math
-
Insights Why Vector Spaces Explain The World: A Historical Perspective
- Started by fresh_42
- Replies: 0
- General Math