Pendulums colliding - collision

  • Thread starter Thread starter superdave
  • Start date Start date
  • Tags Tags
    Collision
AI Thread Summary
The discussion focuses on calculating the maximum angular displacement of two colliding pendulum balls. The upper ball, with a mass of 2.00 kg, is released from a height of 10.0 cm above the lower stationary ball, which has a mass of 3.00 kg. Participants suggest using conservation of energy to determine the speed of the upper ball just before impact and then applying conservation of momentum for the inelastic collision. After finding the combined speed post-collision, they recommend using energy conservation again to calculate how high the masses swing together, which will help determine the maximum angular displacement. The conversation concludes with a participant successfully resolving a trigonometric challenge related to the geometry of the situation.
superdave
Messages
149
Reaction score
3
In the figure View Figure the upper ball is released from rest, collides with and the stationary lower ball, and sticks to it. The strings are both 50.0 cm long. The upper ball has mass is 2.00 kg and it is initially 10.0 cm higher than the lower ball, which has mass 3.00 kg.

yf_Figure_13_36.jpg


Find the maximum angular displacement of the motion after the collision.

I've found omega, if that helps.
 
Physics news on Phys.org
since we don't know what omega is, it doesn't.

Convert the potential energy the ball being held up starts with into the kinetic energy it will have when it strikes the bottom ball. Then use conservation of momentum for an inelastic collision, and convert the new kinetic energy to the maximum potential energy the system can achieve. From there, use trig
 
superdave said:
In the figure View Figure the upper ball is released from rest, collides with and the stationary lower ball, and sticks to it. The strings are both 50.0 cm long. The upper ball has mass is 2.00 kg and it is initially 10.0 cm higher than the lower ball, which has mass 3.00 kg.

yf_Figure_13_36.jpg


Find the maximum angular displacement of the motion after the collision.

I've found omega, if that helps.

Use conservation of energy to find the speed of the first mass just before it hits the second one. Then use momentum conservation to find the speed of the two masses combined just after the collision (when they are still at the lowest point). Finally, use conservation of energy again to find how high they will swing up. Once you have that, simple geometry will give you the angle they reach.
 
can you give me a hint with the trig? Because I can only find one side, and the right angle. I need at least one more angle or side.
 
nevermind, I got it. Thanks for the help.
 
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}...

Similar threads

Back
Top