D. Equal to zero.
Because the forces balance each other.
The scale would need 10 aluminum cubes on one side. Figure out how many paper clips would be needed on the other side to balance this. You have to use more than one aluminum cube because you need to have enough cubes so that you get a whole number mass. 10 cubes gives you a total mass of 27 g for the aluminum.
C. Acceleration is the rate of change of velocity. So at the top of the path, while the velocity is zero, the CONSTANT GRAVITATIONAL ACCELERATION is about 10 m/s^2 (9.8)
if in series one lightbulb burns out the rest are unable to turn on.
In parallel a single light bulb burns out any other light bulbs are able to work.
Parallel is the best to use during holidays.