A bar weighing 300 g falls vertically downward with an acceleration of 8 m / s2. What is the force of air resistance.

According to Newton’s second law:

ma = Ft – Fc, where m is the mass of the bar (m = 300 g = 0.3 kg), a is the acceleration of the bar (a = 8 m / s²), Ft is the force of gravity acting on the bar (Ft = m * g , where g is the acceleration of gravity (we take g = 10 m / s²)), Fс is the force of air resistance.

Let us express and calculate the force of air resistance:

Fc = Ft – ma = m * g – m * a = m * (g – a) = 0.3 * (10 – 8) = 0.3 * 2 = 0.6 N.

Answer: The force of air resistance is 0.6 N.