The lift moves downward with an acceleration of 0.004m / s2. Determine the boy’s weight if his weight is 35 kg.

Given:

a = 0.004 m / s ^ 2 – the acceleration with which the elevator moves (downward);

m = 35 kg – the weight of the boy;

g = 10 m / s ^ 2 – free fall acceleration.

It is required to determine the boy’s weight P (Newton).

According to Newton’s third law:

P – Fт = – m * a =

P = Ft – m * a = m * g – m * a = m * (g – a) = 35 * (10 – 0.004) = 35 * 9.996 = 349.9 N.

Answer: the boy’s weight is 349.9 Newtons.