With what acceleration will a body with a mass of 400 g move under the action of the elastic force from the side

With what acceleration will a body with a mass of 400 g move under the action of the elastic force from the side of the spring k = 40 N / m, stretched by 20 cm. Other forces do not act on the body.

Task data: m (body weight) = 400 g (in SI m = 0.4 kg); k (stiffness of the spring used) = 40 N / m; Δx (spring deformation) = 20 cm (in SI Δx = 0.2 m).

The acceleration that the taken body will acquire from the side of the spring can be expressed from the equality: Ek = En and m * V ^ 2/2 = k * Δx ^ 2/2, whence V = √ (k * Δx ^ 2 / m).

Let’s calculate: V = √ (40 * 0.2 ^ 2 / 0.4) = 2 m / s.

Answer: Under the action of the elastic force, the taken body will acquire a speed of 2 m / s.