Conservation of kinetic energy/linear momentum problem

AI Thread Summary
An 8-kg sphere A collides with a 10-kg block B on a 45° incline, with A moving left at 15 m/s and B moving right at 5 m/s. The problem involves perfectly elastic collision, requiring the conservation of kinetic energy and linear momentum equations to find the final velocities of both objects post-impact. The incline's angle affects the analysis, necessitating the resolution of block B's velocity into horizontal and vertical components. The height of the collision above the ground is considered irrelevant to the calculations. Proper application of the equations will yield the final speeds of both A and B after the impact.
jhahler
Messages
15
Reaction score
0

Homework Statement


An 8-kg sphere A is moving to the left with a velocity of 15 m/s when it strikes the 45° inclined surface of a 10-kg block B which is moving to the right a 5 m/s. The ball strikes the block 1 meter above the ground. The block is supported by rollers and impact is perfectly elastic. Determine the speeds of A and B after the impact.


Homework Equations


1/2mb(vb)^2 + 1/2ma(va)^2 = 1/2mb(vb)^2 + 1/2ma(va)^2 (initial kin. energy = final kin. energy)
mbvb + mava = mbvb + mava (initial linear mom. = final linear mom.)

The Attempt at a Solution


I know to use those 2 equations to solve for the 2 unknowns Vb final and Va final, but the only thing that's messing me up is what to do with the 45° incline on the block, and I think that the ball striking the block 1 foot about the ground is irrelevant, but I'm not positive. Any help is much appreciated.
 
Physics news on Phys.org
Try and resolve the 'v' of the inclined block into its horizontal component. And then put the derived 'v' into the equation.
 
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 '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