A car accelerates along a straight road from rest to 21m/s in 5 seconds. What is the magnitude of it's average acceleration?
a = ∆v/∆t = (21 m/s) / 5s = 4.2 m/s^2
Homework
To find the magnitude of the average acceleration of the car, we need to use the formula for average acceleration, which is defined as the change in velocity divided by the time taken.
Average acceleration (a) = Change in velocity / Time taken
In this case, the car starts from rest (0 m/s) and achieves a final velocity of 21 m/s in 5 seconds. The change in velocity is the final velocity minus the initial velocity.
Change in velocity = Final velocity - Initial velocity
Change in velocity = 21 m/s - 0 m/s
Change in velocity = 21 m/s
Now, we can substitute the values we found into the formula for average acceleration.
Average acceleration (a) = Change in velocity / Time taken
Average acceleration = 21 m/s / 5 seconds
Average acceleration = 4.2 m/s^2
Therefore, the magnitude of the average acceleration of the car is 4.2 m/s^2.