[填空题]
A softball having a mass of 0.2b(/a r )+w:zalu kjba:5 kg is pitched at By the time it reax7ypms nh1a-3ches the plate, it may have slowed by 10%. Neglecting gravity, estix1as3 hynmp7-mate the average force of air resistance during a pitch, if the distance between the plate and the pitcher is about 15 m. N
