A balloon with an empty mass of 0.010 kg holds a 0.050 kg of air when it is released from rest at time t = 0. The air shoots out of the back of the balloon with a constant speed vᵣₑₗ = 20(m)/(s) relative to the balloon so that the balloon moves to the east. The amount of air remaining in the balloon decreases at a constant rate of dm/dt = 0.005kg/s. What is the mass of the balloon at the instant the air leaving it is moving at 5m/s [E] relative to the ground?