Kaila still likes getting her revenge on Tesla owners, but she doesn't like having to get her bumper fixed each time. So Kaila decides to fix her $3,500$ kg Cadillac Escalade with a large spring, so that during "collisions" the two vehicles do not touch.

Kaila is driving to the grocery store when she sees Ben testing a $3,000$ kg Tesla "Cybertruck". Even though Kaila is busy, she's never seen a cybertruck before and has to hit it$.$ So while Ben is stopped at a light, Kaila accelerates to a speed of $70$ mph $(31\mathrm{.}3$ m$/$s$)$ and rear ends Ben's "Cybertruck". With her spring sending it flying into the intersection. How fast is Ben going after the collision?