A0.20 kg object, attached to a spring with spring constant k = 10 n/m, is moving on a horizontal frictionless surface in simple harmonic motion of amplitude of 0.080 m. what is its speed at the instant when its displacement is 0.040 m? (hint: use conservation of energy.)

 v = 0.566 m / s

Explanation:

Let's use energy conservation at two points the most extreme point of maximum elongation and the point of interest

Initial maximum elongation

    Em₀ = = ½ k x²

At this point x = A = 0.080 m

Final point of interest

    = K = ½ m v²

Energy is conserved

   Em₀ =

   ½ k A² = ½ m v²

   v² = k / m A²

   v = √(k/m) A

Let's calculate

   v = √ (10 / 0.20) 0.080

   v = 0.566 m / s

it's when something is going so fast it makes a loud noise, breaking the sound barrier, for example: a jet makes a loud noise, not only cause of the jet but because they reached a point where they went so fast that you can year the noise from various parts, kinda like a police car, lets say the car was going   so fast that you hear the siren of the cop car right next to you, but the car is probably a mile a way, it's cos the siren was next to you a few seconds if you understand me