# Inertia for a large mass (in outer space)

I understand that an object doesn't need a force to keep moving; that it will keep moving indefinitely in that direction at that speed. My question though is: if you were in outer space, where friction is not an issue like on earth, could you move an object with the same mass as a house just by lightly tapping it? My understanding, which probably isn't 100% correct, is that inertia means how much an object resists a change in motion. So is it even possible that an object floating in outer space, with mass the size of a house, could stay still from just a small push? Or would it move, just slowly, because force always causes some degree of acceleration?

• it will move , slowly but move – user83548 Jun 5 '16 at 22:31

\begin{align}\Sigma p_{0} &= \Sigma p_{f}\\ 0 &= mv + MV \\ v &= - (M/m)V \end{align}