1. Identify the Forces

* Gravity: The balloon experiences a downward force due to gravity, calculated as F_gravity = m * g, where m is the mass (2 kg) and g is the acceleration due to gravity (approximately 9.8 m/s²).

* Buoyancy: The balloon experiences an upward force due to buoyancy, calculated as F_buoyancy = ρ_air * V * g, where ρ_air is the density of air (approximately 1.2 kg/m³) and V is the volume of the balloon (5 m³).

2. Calculate the Net Force

The net force acting on the balloon is the difference between the buoyancy force and the gravitational force:

F_net = F_buoyancy - F_gravity

3. Apply Newton's Second Law

Newton's Second Law states that F_net = m * a, where a is the acceleration. We can rearrange this to solve for acceleration:

a = F_net / m

4. Substitute and Calculate

* F_gravity = (2 kg) * (9.8 m/s²) = 19.6 N

* F_buoyancy = (1.2 kg/m³) * (5 m³) * (9.8 m/s²) = 58.8 N

* F_net = 58.8 N - 19.6 N = 39.2 N

* a = (39.2 N) / (2 kg) = 19.6 m/s²

Therefore, the initial acceleration of the balloon is 19.6 m/s² upward.