Answer:
The terminal speed of this object is 12.6 m/s
Step-by-step explanation:
It is given that,
Mass of the object, m = 80 kg
The magnitude of drag force is,

The terminal speed of an object is attained when the gravitational force is balanced by the gravitational force.



On solving the above quadratic equation, we get two values of v as :
v = 12.58 m/s
v = -15.58 m/s (not possible)
So, the terminal speed of this object is 12.6 m/s. Hence, this is the required solution.