The drag force magnitude is determined by Fd = -1/2*rho*v2*Cd*A.

Where rho represents the air density, v the velocity, and Cd the drag coefficient.

A is the cross-sectional area. The terminal velocity, vt will be equal to the gravitational force.

1/2*rho*vt^2*Cd*A = m*g

Because the drag force is proportional with the square of velocity, doubling the velocity will increase the drag force by a factor of 4.

Fd = 1/2*rho*(2*vt)^2*Cd*A

Fd = 1/2*rho*4*vt2*Cd*A

Fd = 4*(1/2*rho*vt^2*Cd*A)

Fd = 4*m*g

The drag force is therefore 4 times greater than the acceleration caused by gravity. m*a = 4*m*g

a = 4*g

The acceleration is 4*g. The drag force will always oppose the motion of the ball. If the ball is shot straight up gravity will oppose the drag force. This is how it works.

a = 4*g + 5g

a = 5*g

The drag force acts in the opposite direction of gravity when the ball is shot downwards.

a = 4*g – g

a = 3*g

Number 1 = 5, and number 2 = 3.