Log in

View Full Version : Force


anime10
Sep 8, 2013, 06:48 PM
If something is moving fast, does that mean that there is a large force acting on it?

My answer: I think that the answer is yes because in order for an object to move it must have a force? Does my question make sense or am I confusing the concept of force and motion.

ebaines
Sep 9, 2013, 05:40 AM
You're confusing things. The term "moving fast" means the object has high velocity. From F=ma you know that acceleration is force divided by mass, so high acceleration implies a large force (or a small mass). But once the object has been accelerated and is moving fast no additional force is necessary for it to remain movng fast. For example consider a bullet that is fired out of a gun - it certainly experiences a high force to accelerate, but once it leaves the muzzle of the gun it no longer has any force pushing it along yet remains at very high speed until it hits its target.