Question

multiple select question
select all that apply
a car traveling in a straight line has a constant acceleration of 3 m/s². based on this information, which of the following statements below is correct?
□ every second the car will change its speed by 3 m/s.
□ for the first second the car will change its speed by 3 m/s, but we dont know what will happen after that.
□ every second the car will have a speed of 3 m/s.
□ the car will change its velocity by 6 m/s after 2 seconds.
□ the car will change its speed by 1 m/s in a third of a second.

Explanation:

Step1: Define constant acceleration

Constant acceleration $a = 3\ \text{m/s}^2$ means speed/velocity changes by $3\ \text{m/s}$ each second, per $\Delta v = a \Delta t$.

Step2: Evaluate each statement

• Statement 1: $\Delta v = 3\ \text{m/s}^2 \times 1\ \text{s} = 3\ \text{m/s}$, correct.
• Statement 2: Acceleration is constant, so change is same every second, incorrect.
• Statement 3: Initial speed is unknown, so final speed can't be found, incorrect.
• Statement 4: $\Delta v = 3\ \text{m/s}^2 \times 2\ \text{s} = 6\ \text{m/s}$ (straight line, velocity = speed change), correct.
• Statement 5: $\Delta v = 3\ \text{m/s}^2 \times \frac{1}{3}\ \text{s} = 1\ \text{m/s}$, correct.

Answer:

• Every second the car will change its speed by 3 m/s.
• The car will change its velocity by 6 m/s after 2 seconds.
• The car will change its speed by 1 m/s in a third of a second.