An airplane is brought to rest in a distance of 1,300 m using a constant acceleration of 3.0 m/s2. What was the velocity of the airplane when the acceleration first began?

1 answer

To find the initial velocity of the airplane when it first began to decelerate, we can use the equations of motion. In this case, we can use the following equation:

\[ v^2 = u^2 + 2as \]

Where:

  • \( v \) = final velocity (0 m/s, since the airplane comes to rest)
  • \( u \) = initial velocity (what we're trying to find)
  • \( a \) = acceleration (which will be negative since it's deceleration, so we use -3.0 m/s\(^2\))
  • \( s \) = distance (1,300 m)

Rearranging the equation to solve for \( u^2 \):

\[ 0 = u^2 + 2(-3.0)(1300) \]

This simplifies to:

\[ 0 = u^2 - 7800 \]

Now, we can solve for \( u^2 \):

\[ u^2 = 7800 \]

Taking the square root to find \( u \):

\[ u = \sqrt{7800} \]

Calculating the square root:

\[ u \approx 88.37 , \text{m/s} \]

Therefore, the velocity of the airplane when the acceleration first began was approximately 88.37 m/s.