A baseball with a mass of 0.145 kg is thrown straight down at the ground. At a particular speed, it has a drag force of 0.4 N acting on it. What is its acceleration at that time?

a. -7.0 m/s2
b. -2.8 m/s2
c. -9.8 m/s2
d. -12.6 m/s2

1 answer

.4 N up
9.8*.145 down

m a = .4 - 9.8*.145

that is about .4 - 1.4 or -1
a = -1/.145 = about -7

a