Question

A car begins from a standstill and reaches a velocity of 42 m/s after 7.0 seconds. What is the average acceleration of the car?

(1 point)
Responses

2.9 m/s2
2.9 m/s 2

7.0 m/s2
7.0 m/s 2

6.0 m/s2
6.0 m/s 2

0.17 m/s2

Answer 1

To find the average acceleration of the car, we can use the formula for acceleration:

\[
a = \frac{{\Delta v}}{{\Delta t}}
\]

where:
- \( a \) is the average acceleration,
- \( \Delta v \) is the change in velocity,
- \( \Delta t \) is the change in time.

In this case:
- The car starts from a standstill, so the initial velocity (\( v_0 \)) is 0 m/s.
- The final velocity (\( v_f \)) is 42 m/s.
- The time taken (\( \Delta t \)) is 7.0 seconds.

Now, calculate the change in velocity (\( \Delta v \)):
\[
\Delta v = v_f - v_0 = 42 \, \text{m/s} - 0 \, \text{m/s} = 42 \, \text{m/s}
\]

Now, plug the values into the acceleration formula:
\[
a = \frac{{42 \, \text{m/s}}}{{7.0 \, \text{s}}} = 6.0 \, \text{m/s}^2
\]

Thus, the average acceleration of the car is **6.0 m/s²**.