Please help this is really confusing

Rank the six combinations of electric charges on the basis of the electric force acting on q1. define forces pointing to the right as positive and forces pointing to the left as negative. rank positive forces as larger than negative forces. q1,q2,q3 = positive(+) q1 = + q2 = + q3 = - q1 = + q2= - q3= + q1= - q2= + q3= + q1= + q2= - q3= - q1,q2,q3 = negative

Scientific models are based on current knowledge, which can limit their effectiveness when new discoveries are made.

Aball is thrown vertically upwards from the top of a tower with a speed of 100m/s.it strikes the pound near the base of the tower after 25sec . the height of the tower is