Newton's First Law?

Question

To pull a wagon across a lawn with constant velocity, you have to exert a steady force. Reconcile this fact with Newton's first law, which says that motion with constant velocity requires no force.

Please help!

Answer 1

Your version of Newton's 1st should say "... requires zero net force" The force you apply to the wagon is equal and opposite the force of friction -- leaving a net force of zero.

Answer 2

Yes, friction is a force. There are two types of friction: static friction and kinetic friction, and between the two, static friction is much stronger. That is why it is harder to get something moving than to keep it moving, and why things suddenly lurch out of control when you apply significant force to get an object moving. The coefficient of kinetic friction is often much lower than the coefficient of static friction.

In the extremely low density regions of space (i.e. the interplanetary, interstellar and intergalactic "voids"), the amount of frictional forces available to slow spacecraft or other objects approaches zero, so in space, to arrive safely at your destination requires deliberate application of force. In "outer space" vehicles and objects behave much closer to the newtonian ideal, whose mechanics are still used in sending space vehicles to other worlds.

Answer 3

friction