[填空题]
A 0.145-kg baseball pitched at 39lgz 2zb4z9z)1f/ bs2 z,kbbhr m/s is *njja5k k d1c(kj903-dvws tt hit on a horizontal line drive straight back toward the pitcher at 52m/s Ia 1j knkw0v5(d9j3d -tk*c jstf the contact time between bat and ball is $3\times10^{-3}$s calculate the average force between the ball and bat during contact. N
