If and object accelerates from rest, with a constant acceleration of 5.4m/s2,what will its velocity be after 28s

Balloon a has charge q, and identical mass balloon b has charge 10q. you hang them from threads near each other. choose all of the statements with which you agree. check all that apply. a. a and b exert the same magnitude forces on each other. b. the force that a exerts on b is 10 times the force that b exerts on a. c. the angle between the thread supporting a and the vertical is < the angle between the thread supporting b and the vertical. d. the force that a exerts on b is 1/10 the force that b exerts on a.

Ihave a density of 1.61g/cm^3 and a mass of 28g. find the missing value

What’s #16 asking and how do i solve it?