Can someone please help me quick :(
A toy spring with a spring constant of 6.4 N/m has a relaxed length of 20.0 cm. When a ball is attached to the end of the spring and allowed to come to rest, the vertical length of the spring is 75.0 cm. What is the elastic potential energy stored in the spring

Four point charges each having charge q are located at the corners of a square having sides of length a. find symbolic expressions for the following. (a) the total electric potential at the center of the square due to the four charges (use any variable or symbol stated above along with the following as necessary: ke.) vtotal= (b) the work required to bring a fifth charge p from infinity to the center of the square (use any variable or symbol stated above along with the following as necessary: w=