How Do You Determine the Period of a Non-SHM System Using Energy Equations?

AI Thread Summary
To determine the period of a non-simple harmonic motion (non-SHM) system using energy equations, the potential energy function U(x) is given as U(x)=U0(x/a)^1000000. The total energy E is expressed as E=U+K, where K is the kinetic energy. The discussion emphasizes the need to derive the force from the potential energy using F(x)=-dU/dx and to solve the resulting differential equation. Participants express confusion about whether the problem relates to spring or pendulum systems and seek clarification on the integration process for finding the period. The consensus is that the system does not exhibit simple harmonic motion characteristics.
Physicist_FTW
Messages
8
Reaction score
0
1. U(x)=U0(x/a)^1000000
Find the period for a mass m, if it has total energy E


2. E=U+K




3. dE/dt=0=v[mdv/dt+dU/dx]

I am really stuck on this one, I am not sure what to do at all talked to my proffessor he says just to re-read the chapter but if I am honest I've always been one to learn through examples which he hasnt given us, any clues would be most appreciated!
 
Physics news on Phys.org
Physicist_FTW said:
1. U(x)=U0(x/a)^1000000
Find the period for a mass m, if it has total energy E


2. E=U+K




3. dE/dt=0=v[mdv/dt+dU/dx]

I am really stuck on this one, I am not sure what to do at all talked to my proffessor he says just to re-read the chapter but if I am honest I've always been one to learn through examples which he hasnt given us, any clues would be most appreciated!


Is this a spring and mass problem, or a pendulum problem or what? Please post more details and the relevant equations in more detail, and show us how you have tried to start the solution...
 
its a SHM probelm, well i tried
-dU/dx=F(x)
F(x)=m(d^2x/dt^2)
then i think I am meant to guess a value for x(t) but I am not really sure/
 
Physicist_FTW said:
its a SHM probelm, well i tried
-dU/dx=F(x)
F(x)=m(d^2x/dt^2)
then i think I am meant to guess a value for x(t) but I am not really sure/

First I suggest that you express the potential energy as:

U(x)=\frac{U_0}{a^{k+1}}x^{k+1} where in our case k+1=1000000

Use the following theorem:

F(x)=-U'(x)

And from there all that remains is to solve a tricky differential equation. I'm trying it myself, it looks interesting.
 
If E=U+K
E=((U0x^K+1)/a^k+1)+0.5(m)(dx/dt)^2
rearrange
dx/dt=(2/m(E-U0x^K+1)/a^k+1))^0.5
is this the right way about, I am not sure how to do this integral.
 
This system doesn't look to be SHM.
 
Thread 'Variable mass system : water sprayed into a moving container'
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 thinking using 2 purple mattress samples, and taping them together, I do want other ideas though, the main guidelines are; Must have a volume LESS than 1600 cubic centimeters, and CAN'T exceed 25 cm in ANY direction. Must be LESS than 1 kg. NO parachutes. NO glue or Tape can touch the egg. MUST be able to take egg out in less than 1 minute. Grade A large eggs will be used.
Back
Top