Ns means Newton-seconds which is "newtons times seconds"
because Ns is shorthand for N*s (the minus sign is actually a dash which is confusing, so they usually just write Ns)

Nhr means Newton-hours which is "newtons times hours."
Nhr is shorthand for N*hr

Newtons per seconds would be written N/s

Newtons per hour would be N/hr

Newton second = Ns

Newtons per second = N/s

http://en.wikipedia.org/wiki/Newton-second