Force equals rate of change of momentum Steps:

• Recall that resultant force F = dp/dt, the slope of the p-t graph.
• Locate t=5s on the graph to find the tangent's slope.
• Measure the slope at that point: Δp/Δt = 3000 kg m/s over 2 s = 1500 N.
• Conclude the force is 1500 N.

Why B is correct:

• Newton's second law states F = dp/dt; the graph's slope at t=5s gives exactly 1500 N.

Why the others are wrong:

• A: Slope is not zero (no horizontal tangent at t=5s).
• C: Slope is not 2000 N (Δp/Δt ≠ 2000).
• D: Slope is not 4000 N (Δp/Δt ≠ 4000).

Final answer: B