a) The box weighs 294.21 newtons.
b) Normal force has a magnitude of 294.21 N.
c) Net acceleration of the box is 3.333 meters per square second.
d) <em>Maximum</em> force of static friction is 88.263 newtons.
e) <em>External</em> force must greater than 88.263 newtons to start motion.
<h3>How to use Newton's laws to model a box</h3>
Newton's laws describes the motion of a system considering its causes, which are represented by loads (i.e. moments, forces). Herein the system is a box that only translates itself on the floor, then the system can represented as a particle. Let assume that floor is horizontal:
a) The weight of the box is the product of mass of box and <em>gravitational</em> acceleration:
W = (30 kg) · (9.807 m / s²)
W = 294.21 N
b) The normal force has the same magnitude of the weight but a direction opposite to it:
N = 294.21 N
c) According to the Newton's laws, the net force experimented by the system is equal to the product of the mass of the box and the <em>net</em> acceleration:
100 N = (30 kg) · a
a = 3.333 m / s²
d) The <em>maximum</em> friction force is described by Coulomb's formula, that is, the product of <em>static</em> coefficient of friction and normal force:
f = (0.3) · (294.21 N)
f = 88.263 N
e) Friction force is a <em>reactive</em> force, that is, against <em>motion</em> direction of the system and <em>external</em> forces must be opposite to and greater than friction force to start motion:
P ≥ 88.263 N
To learn more on Newton's laws: brainly.com/question/27573481
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