Newton’s 2nd law example number 1, the easy
case. Recall, Newton’s 2nd law: you have unbalanced
forces, implying that the net force is not zero, meaning that the object is accelerating.
In the case where the unbalanced forces don’t exist, ie you’re in equilibrium, the acceleration
is zero. Trivial example #1.
Let’s suppose I have a wheelbarrow and I’m applying a net force in the horizontal
direction of 5000 N. Let’s suppose that the wheelbarrow has a mass
of 1000 kg. What then is the acceleration?
Note that I quoted a net force here. So, Newton’s 2nd Law says net force equals
mass times acceleration. I’m given two quantities and asked to solve
for the third. Net force quoted in newtons, mass in kilograms
is going to yield an acceleration with units of meters per second per second.
The acceleration is positive, it’s in the same direction as the net force.
This wheelbarrow is accelerating to the right.