# It was once recorded that a Jaguar left skid marks that were 290 m in length. Assuming that the Jaguar skidded to a stop with a constant acceleration of -3.90 m/s2, determine the speed of the Jaguar before it began to skid.

To determine the speed of the Jaguar before it began to skid, we can use one of the kinematic equations of motion. The relevant equation relates initial velocity \( v_0 \), final velocity \( v \), acceleration \( a \), and distance \( d \):
\[
v^2 = v_0^2 + 2ad
\]
In this scenario:
- The final velocity \( v \) is \( 0 \) m/s (since the Jaguar comes to a stop).
- The acceleration \( a \) is \( -3.90 \, \text{m/s}^2 \) (negative because it's deceleration).
- The distance \( d \) is \( 290 \, \text{m} \).
We can rearrange the equation to solve for \( v_0 \):
\[
0 = v_0^2 + 2(-3.90)(290)
\]
Calculating the second term:
\[
0 = v_0^2 - 2 \times 3.90 \times 290
\]
\[
0 = v_0^2 - 2262
\]
\[
v_0^2 = 2262
\]
\[
v_0 = \sqrt{2262}
\]
\[
v_0 \approx 47.6 \, \text{m/s}
\]
Therefore, the speed of the Jaguar before it began to skid was approximately \( \boxed{47.6} \) m/s.