At a distance N X RE from the earth's surface, where N is an integer, the gravitational force on an object is only 1/81 of its value at the earth's surface. What is N?
Express your answer as an integer.

Two technicians are discussing a resistance measurement between the can-h and can-l wires. technician a says this measurement should be done with the ignition switch in the "run" position. technician b states that a measurement of 0 ohms indicates an open in the network. which technician is correct?

We put a force of 50n on an object and the acceleration is 100 m/s². what is the mass of the object?

Which is the correct symbol for an isotope of iodine with 53 protons and 78 neutrons?