Question

2. Which of the following describes the Law of Inertia?
A Equal forces act on an object in the opposite direction
B. An object at rest stays at rest and an object in motion stays in motion
unless acted on by an unbalanced force.
C. The net force is equal to the sum of all the individual forces acting on
an object
D.it is the rate at which velocity changes​

Answer 1

The following describes the law of inertia -

B. An object at rest stays at rest and an object in motion stays in motion unless acted on by an unbalanced force.

• Law of inertia is described by Newton's first law of motion. Inertia is the force by which a body in motion tends to remain in motion and at the same time, a body at rest remains at rest.
• The above situation is valid only if a body travels on a frictionless surface. If friction is acting on the body, then there is no force balancing it.  
• Consequently, the moving body will come to rest after some time.
• Due to inertia, a body at rest tends to remain at rest, for example, passengers in the bus tend to move backwards when the bus starts. And a body in motion tends to remain in motion, for example, passengers in the bus tend to bend forwards when brakes are applied.

A. Equal forces act on an object in the opposite direction -

• The above statement describes the characteristics of action and reaction force depicted by Newton's third law of motion.  

C. The net force is equal to the sum of all the individual forces acting on an object -

• The net force is equal to the vector sum of individual forces, but again this does not explain inertia.

D. Inertia is the rate at which velocity changes​ -

• This statement is not true. The rate at which the velocity of a body changes is its acceleration, not inertia.