Obtain a relation for the distance travelled by an object moving with a uniform acceleration in the interval between 4th and 5th seconds​

How are calculation for velocity and speed different

Idon’t quite understand this problem

Point charges q1 = 51 µc and q2 = −27 µc are placed 1.0 m apart, with q2 on the right. what is the force (in n) on a third charge q3 = 19 µc placed midway between q1 and q2? (assume the positive direction is to the right. indicate the direction with the sign of your answer.)