physics please help
posted by jonathan .
A golfer, driving a golf ball off the tee, gives the ball a velocity of +40 m/s. The mass of the ball is 0.045 kg, and the duration of the impact with the golf club is 4.05E3s.
(a) What is the change in momentum of the ball?
(b) Determine the average force applied to the ball by the club.

This is really a too simple problem.
change of momentum= mass(change in velocity).
average force=changemomentum/timeimpact 
for part a i got change in momentum right which was 1.8 then when i divided that by 4.05E3 i got 4.44E4 and it was marked wrong

I used the same equation as you did for average force, but when I divided change in momentum by time of impact I got 444.
averageforce=changemomentum/timeimpact
=(1.80)/(4.05*10^3)
= 444.4 
3