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Physics F=ma please help

Only one force acts on an object. Can the object have zero acceleration? Can it have zero velocity? Explain.


I understand that the object cannot have 0 acceleration, but according to the book it can have 0 velocity and I don't understand this.
If only 1 force is acting on the object, then the object is definitely moving, then it has a velocity, where am I going wrong ?
Original post by JanaALEVEL
Only one force acts on an object. Can the object have zero acceleration? Can it have zero velocity? Explain.


I understand that the object cannot have 0 acceleration, but according to the book it can have 0 velocity and I don't understand this.
If only 1 force is acting on the object, then the object is definitely moving, then it has a velocity, where am I going wrong ?


Newton's first law: an object will remain at rest or continue it's motion in a straight line unless acted upon by an external force.

I other words, velocity is measured with respect to a reference. For everyday purposes velocity is measured with respect to the ground which to a casual observer is stationary. The ground is the reference.

If a force now acts on the object it will experience an acceleration.If no acceleration is measured, the net forces acting on the object must be 0.

No force = no acceleration = constant straight line velocity OR 0 velocity wrt a stationary reference.

Force produces acceleration = change in direction of increase/decrease in velocity.
(edited 4 years ago)
Reply 2
Original post by uberteknik
Newton's first law: an object will remain at rest or continue it's motion in a straight line unless acted upon by an external force.

I other words, velocity is measured with respect to a reference. For everyday purposes velocity is measured with respect to the ground which to a casual observer is stationary. The ground is the reference.

If a force now acts on the object it will experience an acceleration.If no acceleration is measured, the net forces acting on the object must be 0.

No force = no acceleration = constant straight line velocity OR 0 velocity wrt a stationary reference.

Force produces acceleration = change in direction of increase/decrease in velocity.

I don't think this answers my question
Original post by JanaALEVEL
I don't think this answers my question

The object has zero acceleration only when no forces act on it.

If a force acts on the object, it must accelerate in the direction of the force.

An object can have velocity (straight line motion) even when no forces act on it.

Force produces acceleration.

Acceleration produces a change in velocity.
You've probably been assuming the object is not moving before the force is applied, but this doesn't have to be the case. What happens if it is moving in the opposite direction of the force?
Original post by JanaALEVEL
I don't think this answers my question


It is as @uberteknik answered again:

acceleration means a change in velocity in that way that velocity increases. Velocity itself is neither depend on acceleration nor the force, it can exists without these two units. Velocity is defined in a different way, namely as a distance per time. Velocity is nothing more than the change of the location. Just think about the car as an example for objects with straigt line motion:

in the moment you increase the velocity, you change it by acceleration what in turn means that you apply a force by the accelerator. If your velocity is constant or decreased, no acceleration acts on ,as no force acts on the car's engine to boost.

And that answers the question: "Can the object have zero acceleration? Can it have zero velocity?", yes, it is possible!
(edited 4 years ago)

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