For the manufacture of the slingshot, a rubber cord with a hardness of 400 N / m was used.

For the manufacture of the slingshot, a rubber cord with a hardness of 400 N / m was used. A stone weighing 10 g was shot from a slingshot, placing it in the middle of the cord and pulling with a force of 40 N. At what speed will the stone fly out?

Initial data: k (stiffness of the rubber cord) = 400 N / m; m (stone mass) = 10 g (0.01 kg); F (the force with which the cord was pulled) = 40 N.

1) Determine the elongation of the spring: F = k * Δx, whence Δx = F / k = 40/400 = 0.1 m.

2) We calculate the speed at which the stone will fly out from the equality: Ek = 0.5 * m * V ^ 2 = 0.5 * k * Δx ^ 2, whence V2 = k * Δx ^ 2 / m and V = √ ( k * Δx ^ 2 / m) = √ (400 * 0.1 ^ 2 / 0.01) = 20 m / s.

Answer: The stone flew out of the slingshot at a speed of 20 m / s.