# A car traveling at 92 kmh strikes a tree. The front end of the car compresses and the driver comes to rest after traveling 0.85 m. What was the average acceleration of the driver during the collision?

92km/h = 41*5/3*3 =205/9m/s

v = 205/9 m/s

u = 0m/s

s = 0.85m = 85/100m

a = ?

v2 = u2 + 2as

=> 2052/81 = 2 * a * 85/100

=>a = -0.9766m/s2

### Will the average acceleration be equal to the instantaneous acceleration?

The average acceleration of an object is equal to the instantaneous acceleration of that object if the acceleration is constant (i.e. linear when graphed). However, when there is not constant acceleration, there is no guarantee that the average acceleration is equal to the instantaneous acceleration (i.e. non-linear when graphed).

### What is the equation to solve for average acceleration?

Answer Acceleration = v2 - v1 .........................time Average Acceleration requires you to average the the initial velocity of your trials and the ending velocity of your trials. You must also find the average for your time trials. Once you achieve these numbers, just plug them into the above formula and you can solve for average acceleration.