Impulse-momentum theorem determines average force

Steps:

• From diagram, initial momentum of L is 0.43 kg m/s left (p_i = -0.43 kg m/s, right positive).
• Final momentum of L is 0.12 kg m/s right (p_f = +0.12 kg m/s).
• Change in momentum Δp = 0.12 - (-0.43) = 0.55 kg m/s.
• Average force magnitude F = |Δp| / Δt = 0.55 / 0.08 = 6.9 N.

Why C is correct:

• Matches impulse = change in momentum of L divided by collision time, per impulse-momentum theorem.

Why the others are wrong:

• A: Uses Δp ≈ 0.25 kg m/s, underestimating initial momentum of L.
• B: Uses Δp = 0.32 kg m/s, assuming smaller initial |p_L| ≈ 0.20 kg m/s.
• D: Uses Δp ≈ 0.57 kg m/s, overestimating initial |p_L| ≈ 0.45 kg m/s.

Final answer: C