Producing electricity in power stations is not very efficient. in power station a, 800 joules of energy from coal produce 300 joules of electrical energy.

calculate the efficiency of this power station.

Four objects each with charge +2.0×10−7c are located at the corners of a square whose sides are 2.0 m long. part a what quantities can be determined using this information? check all that apply. the electric force on a charged object placed at the center of the square. the mass of each object. the total electric potential energy of the system consisting of the four charged objects. part b find the electric force on a charged object placed at the center of the square.

Achild has maximum walking speed of 1.6 m/s. what is the length of the child's legs? 0.26 m

Your friend increases her force on the desk by 30n . she doesn't change the direction of her push . what happens to the net force on the desk .will the desk accelerate