Which of these statements are true about hydroelectric power? Check all that are true. It is the most widely used renewable energy source in the world. It never disrupts ecosystems. It is not always available. A hydroelectric dam controls the force of moving water to generate electricity.

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=