In fig. 8.11, determine the character of the collision. The masses of the blocks
ID: 2029085 • Letter: I
Question
In fig. 8.11, determine the character of the collision. The masses of the blocks, and the velocities before and after are given. The collision is:
A) completely inelastic
B) partially inelastic
C) perfectly elastic
D) characterized by an increase in kinetic energy
E) not possible because momentum is not conserved.
In fig. 8.11, determine the character of the collision. The masses of the blocks, and the velocities before and after are given. The collision is: A) completely inelastic B) partially inelastic C) perfectly elastic D) characterized by an increase in kinetic energy E) not possible because momentum is not conserved.Explanation / Answer
Lets see if it obeys the conservation of momentum:
we use m1v1i + m2v2i = m1v1f + m2v2f
2(.8) + (8)(-2) = 2(-1.2) + 8(1.2)
1.6 - 16 = -2.4 + 9.6
-14.4 = 7.2
as you can see they are NOT equal, therefore momentum isn't conserved, so the correct answer is E)
We don't even need to bother solving for the energies to find if it is elastic or inelastic.