Question

which of these collisions demonstrate momentum conservation? (arrows indicate the direction of the momentum.) select all that apply. if none of the collisions demonstrate momentum conservation, then tap on the no answer button.
collision a
before collision
a (p = 30 kg·m/s, arrow right) b (p = 15 kg·m/s, arrow right)
after collision
a (p = 20 kg·m/s, arrow right) b (p = 25 kg·m/s, arrow right)
collision b
before collision
a (p = 26 kg·m/s, arrow right) b (p = 18 kg·m/s, arrow right)
after collision
a (p = 14 kg·m/s, arrow right) b (p = 22 kg·m/s, arrow right)
collision c
before collision
a (p = 50 kg·m/s, arrow right) b (p = 27 kg·m/s, arrow right)
after collision
a (p = 38 kg·m/s, arrow right) b (p = 39 kg·m/s, arrow right)

Explanation:

Step1: Calculate total momentum before Collision A

$p_{\text{total, before A}} = 30 + 15 = 45 \, \text{kg·m/s}$

Step2: Calculate total momentum after Collision A

$p_{\text{total, after A}} = 20 + 25 = 45 \, \text{kg·m/s}$

Step3: Calculate total momentum before Collision B

$p_{\text{total, before B}} = 26 + 18 = 44 \, \text{kg·m/s}$

Step4: Calculate total momentum after Collision B

$p_{\text{total, after B}} = 14 + 22 = 36 \, \text{kg·m/s}$

Step5: Calculate total momentum before Collision C

$p_{\text{total, before C}} = 50 + 27 = 77 \, \text{kg·m/s}$

Step6: Calculate total momentum after Collision C

$p_{\text{total, after C}} = 38 + 39 = 77 \, \text{kg·m/s}$

Step7: Compare before/after momentum for each collision

Momentum is conserved if $p_{\text{total, before}} = p_{\text{total, after}}$.

Answer:

Collision A, Collision C