# If I am moving an object by my thumb at a constant velocity, does it mean I am applying a force on it?

Is there any force on the object being applied in that case? I think there is not since acceleration is zero. So does that mean no force is also being applied back on my thumb?

Also, when the object was rest. And at that instant, when I applied the force on object to impart a certain velocity in it, it should have applied a force back on my thumb in the opposite direction. So the acceleration on my thumb should have been in opposite direction to the direction of the force applied on the object. So, my thumb should have moved in opposite direction, but why does it move in the direction of the object? I am really confused.

Following proton's answer, one part of your question can be answered as follows. In space, an object will move at constant velocity (possibly zero) without any force applied (from your thumb for example). So you could give it a small nudge, and then it would continue with constant velocity without you applying any further force. On the other hand, when the object is sitting on a surface on Earth, then when the object is moving across the surface, that surface provides a force (friction) in the opposite direction to the motion, so that its velocity is reduced and generally quickly brought to zero. Hence in order to maintain a constant velocity for the object, you will have to be constantly providing a force, by continuing to push with your thumb. In terms of Newton's second law (as applied to the forces acting on the object), the acceleration can be zero because we have $m_{\text{object}}a_{\text{object}}=F_{\text{thumb}}-F_{\text{friction}}$ and these two forces can cancel if you push with the right force.