# A trolley with sand with a total mass of 10 kg moves without friction on a horizontal surface at a speed of 2 m, s

**A trolley with sand with a total mass of 10 kg moves without friction on a horizontal surface at a speed of 2 m, s. A ball with a mass of 2 kg flies behind the trolley with a horizontal speed of 8 m, s. After hitting the sand, the ball gets stuck in it. What speed does this acquire cart?**

These tasks: movement in one direction; inelastic collision; mt (weight of the cart with sand) = 10 kg; Vt (initial trolley speed) = 2 m / s; msh (ball mass) = 2 kg; Vsh (initial speed of the ball) = 8 m / s.

To find the speed of the considered cart with sand after the ball hits, we use the equality: mt * Vt + msh * Vsh = (mt + msh) * V, whence we express: V = (mt * Vt + msh * Vsh) / (mt + msh) …

Calculation: V = (10 * 2 + 2 * 8) / (10 + 2) = 3 m / s.

Answer: After hitting the ball cart, it will begin to move at a speed of 3 m / s.