In fair weather, there is an electric field at the surface of the earth, pointing down into the ground. what is the sign of the electric charge on the ground in this situation?

Does anyone know how to solve this problem? i really need . i made an attempt but i just cant get it. a metal rod is 25.000 cm long at 25.0 degrees celsius. when heated to 102.0 degrees celsius, it is 25.054 cm long. what is the coefficient of linear expansion for this metal.

For most stars, what does a higher temperature tend to to with? a lower luminosity a higher luminositya red color none of the above

Which statements describe how a machine can make work easier? check all that apply. it can put out more force than the input force by decreasing the distance through which force is applied. it can increase the amount of work performed if the output force is in the same direction as the input force. it can apply a force to an object in a different direction than the force applied to the machine. it can increase the distance through which a force acts by exerting less force than was used on it. it can exert a greater force through a greater distance than the force used on the machine.