A ball weighing 100 g hangs on an elastic band, the stiffness of which is 1 N / cm. Determine how much the elastic is stretched.

m = 100 g = 0.1 kg.

g = 10 m / s2.

k = 1 N / cm = 100 N / m.

x -?

The balance of a ball on an elastic band is determined by 1 Newton’s law, according to which the resultant of all forces is equal to 0. In other words, the force of gravity of the ball Ft is compensated by the elastic force of the elastic band Ffr: Ft = Ffr.

The force of gravity Ft and the force of elasticity Fcont are expressed by the formulas: Ft = m * g, Fcont = k * x.

m * g = k * x.

x = m * g / k.

x = 0.1 kg * 10 m / s2 / 100 N / m = 0.01 m = 1 cm.

Answer: when hanging the ball, the elastic will stretch x = 1 cm.