Answer:
It's option 4, 647n!
Step-by-step explanation:
Ff = μFn
Assuming it's a flat surface, Force normal is equal to the force of gravity. Since the mass is given in kg, we multiply the mass by 9.81 (acceleration due to gravity).
110 x 9.81 = 1079.1
Now we know the force of gravity and the coefficient of friction, we just multiply them.
Ff = 1079.1(0.6) ≈ 647 N