The units #"kg"*"m/s"# are units of momentum. We represent the momentum vector with #vecp#; its equation in terms of the velocity vector, #vecv#, is:
#vecp=mvecv" [1]"#
where #m# is the mass of the object.
The Newton, #"N"#, is a unit of force. We represent the force vector, #vecF#, with the equation:
#vecF = mveca" [2]"#
where #m# is the mass of the object.
Divide equation [1] by equation [2]:
#vecp/vecF=(mvecv)/(mveca)#
Please observed #m/m# becomes 1:
#vecp/vecF=vecv/veca" [3]"#
We know that constant force produces a constant acceleration and the following equation is true:
#vecv = vecat#
Solve for t:
#t = vecv/veca" [4]"#
Substitute equation [4] into equation [3]:
#vecp/vecF=t#
Substitute #vecp = 620" kg"*"m/s"# and #vecF = 6" N"#
#t = (620" kg"*"m/s")/(6" N")#
#t ~~ 103.3" s"#
