a.
When an unbalanced force acts on an object, net force acts on the object and as a result of this net force , the object accelerates in the direction of the unbalanced force.
b.
When two unequal forces act on an object in opposite direction, there is net force on the object in the direction of the greater of the two forces. Hence the object accelerates in the direction of greater force.
c.
When two equal forces act on an object in opposite direction, they cancel out each other and there is no net force on the object . Hence the object does not accelerate.
