David is traveling at 20 m/s in a car when the car hits the tree. David comes to a complete stop in 0.4 seconds. What is David's acceleration?

david alteration is 20 divide by 0.4 which is 50!

Yes

To find David's acceleration, we can use the formula for acceleration:

Acceleration (a) = (Final velocity - Initial velocity) / Time

In this case, David's initial velocity is 20 m/s (given in the question), his final velocity is 0 m/s (since he comes to a complete stop), and the time is 0.4 seconds (also given in the question).

Now, we can calculate the acceleration:

Acceleration (a) = (0 m/s - 20 m/s) / 0.4 s

Simplifying the equation:

Acceleration (a) = (-20 m/s) / 0.4 s

Acceleration (a) = -50 m/s^2

Therefore, David's acceleration is -50 m/s^2. The negative sign indicates that David's acceleration is in the opposite direction of his initial velocity.