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

$a = \frac{{v_f - v_i}}{t}$

Where:

• $v_f$ is the final velocity (70 km/h)
• $v_i$ is the initial velocity (0 km/h, since the car starts from rest)
• $t$ is the time taken (7 seconds)

Step 1: Convert the final velocity to meters per second (m/s)

Since 1 km/h = $\frac{1000}{3600}$ m/s, we can convert 70 km/h to m/s:

$70 \text{ km/h} = 70 \times \frac{1000}{3600} = 19.44 \text{ m/s}$

Step 2: Apply the acceleration formula

Now we can substitute the values into the formula:

$a = \frac{{19.44 - 0}}{7} = \frac{19.44}{7} = 2.77 \text{ m/s}^2$

Thus, the car's average acceleration is 2.77 m/s².

Would you like more details or have any questions?

Related Questions:

1. How would the acceleration change if the final speed was 100 km/h instead of 70 km/h?
2. What would be the average acceleration if the time taken was 10 seconds instead of 7 seconds?
3. How does average acceleration differ from instantaneous acceleration?
4. If a car has constant acceleration, how can we calculate the distance traveled?
5. What units are used for acceleration, and how do they relate to velocity and time?

Tip:

Always convert speeds to meters per second (m/s) when working with acceleration to keep the units consistent.