Answer:
The force constant for each elastic band is 77.93 N/m
Explanation:
Hooke's law of a spring or an elastic band gives the relation between elastic force (Fe) and stretching (x), the magnitude of that force is:
(1)
With k, the elastic force constant. The three elastic bands support the child’s weight (W) and maintain him at rest, so by Newton’s second law for one of the elastic bands:
(2)
(3)
Using (1) on (3):
(4)

Answer:
Les changements d'état sont des changements physiques. Ils se produisent lorsque la matière absorbe ou perd de l'énergie. Les processus dans lesquels la matière change entre les états liquide et solide sont la congélation et la fusion. Les processus dans lesquels la matière change entre les états liquide et gazeux sont la vaporisation, l'évaporation et la condensation.
Im not french and I used translate so if it messes up with the translation, I am sorry
The amplitude of wave-c is 1 meter.
The speed of all of the waves is (12meters/2sec)= 6 m/s.
The period of wave-a is 1/2 second.