A boy of mass 70 \(kg\) jumps with a horizontal velocity of 7 ms1 onto a stationary cart with frictionless wheels. The mass of the cart is 4 \(kg\).

What is his velocity as the cart starts moving? Assume that there is no external unbalanced force working in the horizontal direction.

Velocity \(=\)  ms1
 
[Note: Enter your answer with 2 decimal digits]