a player uses a hockey stick to increase the speed of a 0.200 kg hockey puck by 6 m/s in 2 seconds how much force was exerted on the puck?

I just did that down below

F = m delta v/delta t = .2 (6/2) = .6 Newtons

or
F delta t = delta m V
F * 2 = .2*6
F = .6 Newtons again