So if force =mass * acceleration, then an object moving at a constant velocity has zero acceleration, and thus force = zero.
So is f=ma actually mean net force or some other definition?
And I’ve been told work is force * distance, so sn object moving at a constant velocity would also have zero work? Which doesn’t sound correct so I’m confused on what exactly work defines
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You are correct that the net force on an object is zero if the velocity is constant.
Let’s just look at the situation where our forces are directed towards the center of mass so they can result in an object starting to rotate around its own axis. We also assume a rigid body ie one that does not deform
Both acceleration and force are vector units so you can start by adding the forces together or do it at the end by adding acceleration together. Matematicaly it is equivalent because mass is a scalar and the samm for all.
An example of adding accelerations is if gravity is involved because the acceleration is independent of the mass but the force depends on the mass.
Work is the amount of energy that is transferred. But for it, you do need to look at the forces separately. Constant velocity if there is no friction air resistance etc requires zero force on an object.
But if you have friction, air resistance, etc it results in a force and will change the velocity, this is why a car will stop on flat ground if you turn off the engine. So the engine of a car provides a force that counteracts friction and air resistance and it does work because it is applied over a distance.
So in the practice of macroscopic objects on earth contact velocity will always require some work.
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