Collision and Kinetic Energy Problem

AI Thread Summary
The discussion focuses on a collision problem involving two balls with different masses and velocities, resulting in an inelastic collision where they stick together. The key questions are about determining the final velocity of the combined mass after the collision and calculating the kinetic energy lost during the event. Participants suggest checking calculations, particularly the y-component of velocity, which may have been incorrectly factored. Additionally, there is a recommendation to clarify the angle of movement in relation to cardinal directions. Accurate calculations and clear angle descriptions are essential for solving the problem effectively.
njuice8
Messages
16
Reaction score
0
A ball, which has a mass of m1 = 2.50 kg., is moving with a velocity of 8.00 m/s at an angle of 25.0˚ South of West. It collides with a second ball, which has a mass of m1 = 1.20 kg., which is moving with a velocity of 4.75 m/s at an angle of 61.0˚ North of West. They stick together and move as one.
What will be the final velocity v3 of the balls after the collision?
How much kinetic energy was lost in this inelastic collision?

I attached a picture of my work
I'm not sure if my work is right.

Also, for the kinetic part, would I just use (1/2)mv^2 = (1/2)mv^2 - Wnc?

Thanks!
 

Attachments

  • DSC02846.jpg
    DSC02846.jpg
    26.1 KB · Views: 522
Physics news on Phys.org
Overall, looks good. But I think you dropped out the factor of 3.7 during the calculation of the y-component which has thrown off your answer for the angle. Also, it's a good idea to state your angle clearly in terms of "south of east" or whatever.
 
Last edited:
I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
Thread 'Collision of a bullet on a rod-string system: query'
In this question, I have a question. I am NOT trying to solve it, but it is just a conceptual question. Consider the point on the rod, which connects the string and the rod. My question: just before and after the collision, is ANGULAR momentum CONSERVED about this point? Lets call the point which connects the string and rod as P. Why am I asking this? : it is clear from the scenario that the point of concern, which connects the string and the rod, moves in a circular path due to the string...
Thread 'A cylinder connected to a hanging mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
Back
Top