Answer:
The speed of of the balloon is about 6.32 m/s
Explanation:
Assuming all of the work done is transformed into the balloon's kinetic energy, we can use the formula for the kinetic energy to answer the question:
[tex]E_k=\frac{1}{2}mv^2\\20J = \frac{1}{2}1kg\cdot v^2\implies v=\pm\sqrt{40\frac{m^2}{s^2}}\approx\pm6.32\frac{m}{s}[/tex]
Speed is the absolute value of velocity, so the speed of the balloon is about 6.32 m/s
