Change in velocity as vector difference

Steps:

• Assign right as positive direction for velocities.
• Initial velocity: +5 m/s (to the right).
• Final velocity: -6 m/s (to the left; note: problem likely intends 6 m/s based on options).
• Calculate Δv = final - initial = -6 m/s - (+5 m/s) = -11 m/s.
• -11 m/s means 11 m/s to the left.

Why C is correct:

• Change in velocity is defined as Δv = v_f - v_i, a vector quantity; here, -11 m/s equals 11 m/s to the left.

Why the others are wrong:

• A: Ignores full reversal; only matches initial speed, not total change.
• B: Wrong direction; change opposes initial motion.
• D: Wrong direction; magnitude correct but sign reversed.

Final answer: C