15 joules of work are done by forces other than gravity in taking an object from position 3 m above the ground to position 8 m above the ground. What is the change in the gravitational potential energy of the object?

Hydrogen and helium are both members of?

Explain what it means to view something from a frame of reference. provide an example that illustrates your explanation. (4 points)

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=