Question

what is best to say about a runner who is running at a constant velocity?
a. their acceleration is positive.
b. their acceleration is negative.
c. their acceleration is zero.
d. their acceleration cannot be determined.
please select the best answer from the choices provided.
a
b
c
d

Explanation:

Acceleration is defined as the change in velocity over time (\(a=\frac{\Delta v}{\Delta t}\)). When a runner has a constant velocity, the change in velocity (\(\Delta v = v_{final}-v_{initial}\)) is zero. Substituting \(\Delta v = 0\) into the acceleration formula gives \(a = 0\).

• Option A: Positive acceleration implies an increase in velocity, which is not the case for constant velocity.
• Option B: Negative acceleration (deceleration) implies a decrease in velocity, which is not the case for constant velocity.
• Option C: As shown by the formula \(a=\frac{\Delta v}{\Delta t}\) with \(\Delta v = 0\), acceleration is zero.
• Option D: The acceleration can be determined using the formula for acceleration when velocity is constant.

Answer:

C. Their acceleration is zero.