Acceleration is the slope of the velocity-time graph

Steps:

• Identify acceleration as the instantaneous slope (gradient) of the v-t graph at a given time.
• At t=0, the slope is given as 3.0 m/s², confirming the graph's initial steepness.
• At t=0.3 s, measure the tangent slope on the graph, which decreases due to changing velocity.
• The slope value at this point is 1.3 m/s², directly giving the acceleration.

Why C is correct:

• Matches the graph's slope at t=0.3 s, per the definition of acceleration as dv/dt.

Why the others are wrong:

• A: Underestimates the slope; possibly confuses with average acceleration over interval.
• B: Incorrect value; ignores the specific tangent at t=0.3 s.
• D: Overestimates; closer to initial slope but not at t=0.3 s.

Final answer: C