what is the acceleration of the car?

Question

Acceleration is sometimes expressed in multiples of g, where is the acceleration due to Earth's gravity. In a car crash, the car's velocity changes from to in In terms of g, what is the acceleration of the car?

26 g
14 g
20 g
24 g

Answer 1

Hi Kristin:

As you can see, something is missing from the question: "velocity changes from to" and neither velocity is given! However, we can infer that the final velocity is zero.

Let's assume the initial velocity is v and the change occurs over time t.

=> The average acceleration, a = change in velocity divided by the time in which the change occurred

= (0 - v) / t = -v / t [this is negative meaning we have a deceleration

To express this in terms of g, we simply divide by the value of g = 9.8 m/s² or 32 ft/s²

Therefore, the required acceleration, a = -v / gt

Once we know v and t, we can plug them into this equation and answer the question!