What is inertia? What is unbalanced force?

inertia is a property of matter by which it continues in its existing state of rest or uniform motion in a straight line, unless that state is changed by an external force.

An unbalanced force is an unopposed force that causes a change in motion

“thy baited hooks shall tangle me no more.”

“hath taught me to set in trifles no store,”

“me lusteth no longer rotten boughs to climb.”

onto a large boat, and mark the water level that the boat sinks to. then, take the elephant out and put a bunch of marked weights onto the boat until it reaches the same water level. add up the masses of the weights to get the weight of the elephant.