Question

1. my race car is going 120m/s as i cross the finish line. i was accelerating at a rate of 9m/s/s for 3 seconds, what velocity was i going when i started to accelerate in order to win? want? equation.

Explanation:

Step1: Recall the acceleration formula

The formula relating final velocity (\(v\)), initial velocity (\(u\)), acceleration (\(a\)) and time (\(t\)) is \(v = u+at\). We need to find the initial velocity \(u\), so we rearrange the formula to \(u=v - at\).

Step2: Identify the given values

We know that the final velocity \(v = 120\space m/s\), acceleration \(a = 9\space m/s^{2}\) (since \(9\space m/s/s=9\space m/s^{2}\)) and time \(t = 3\space s\).

Step3: Substitute the values into the formula

Substitute \(v = 120\), \(a = 9\) and \(t = 3\) into \(u=v - at\):
\(u=120-(9\times3)\)
First, calculate \(9\times3 = 27\). Then, \(u = 120 - 27\).

Step4: Calculate the initial velocity

\(120-27 = 93\).

Answer:

The initial velocity was \(93\space m/s\).