To calculate acceleration, we first need to understand the formula:
Acceleration = (Final Velocity - Initial Velocity) / Time
Here, in this question:
- The initial velocity (u) of the car is given as 0 km/hr.
- The final velocity (v) reached by the car is given as 40 km/hr.
- The time (t) taken for this change in velocity is given as 4 seconds.
One important aspect to keep in mind here is that we need to keep the units of measurement consistent. In this case, velocity is given in km/hr, but time is given in seconds. To make the units consistent, we first need to convert km/hr to m/s because standard unit of acceleration is m/s².
The conversion from km/hr to m/s involves multiplying the velocity by 1000 (to convert kilometers to meters), and then dividing by 60 twice (to convert hours to minutes and then minutes to seconds).
Therefore,
- The initial velocity = 0 km/hr = 0 * 1000 / 3600 m/s = 0 m/s
- The final velocity = 40 km/hr = 40 * 1000 / 3600 m/s = 11.11 m/s (approximately)
Now we can substitute the values into the formula for acceleration:
Acceleration = (Final Velocity - Initial Velocity) / Time
Acceleration = (11.11 m/s - 0 m/s) / 4 seconds
Acceleration = 11.11 m/s / 4
Acceleration = 2.77777 m/s²
So, the car's acceleration was approximately 2.78 m/s².