Pls solve this three questions

Dear student, (50) we know that, v=u+at ,here in this question ball is dropped from rest so u=0, a=10m/s2 and t=9s putting these in the formula we get v=90m/s. (51)If we move from poles to equator the value of acceleration due to gravity "g" – decreases.as we know that the value of g depends on the radius of the earth and When compared to the equator of the earth, the radius is less at the poles, since the earth is considerably flat at the poles.(52)Forces are said to be balanced if there are equal forces acting in opposite directions. Balanced forces are equivalent/Identical to no force at all. If the force of an object is unbalanced, the object will either accelerate or decelerate.