[Chris Hibner]

1. Neglecting air resistance, they will reach the ground at the same time.

2. The force of drag on an object is described by the following equation:

F = 0.5*Cd*rho*A*V^2 (eq 1)

where:

Cd = coefficient of drag
rho = density of air
A = frontal area of the object
V = airspeed of the object

The terminal velocity of the object is when its weight (mass * accel due to gravity) is equal to the force of drag. Thus, the equation becomes:

m*g = 0.5*Cd*rho*A*V^2 (eq 2)

We can then solve eq 2 for V to get the terminal velocity:

V = sqrt[(2*m*g)/(Cd*rho*A)]

Since the two raquetballs are identical except for the mass, the Cd and A are the same for the two balls. Therefore, as the mass increases, the terminal velocity of the ball increases. Hence, the lead filled ball hits the ground first. However, the terminal velocity increases proportionally to the SQUARE ROOT of the mass, (i.e. not directly proportional to the mass).

3. The answers are the same. It doesn't matter for case 1. For case 2, the terminal velocity still increases as the square root of the mass increases.