What is the scientific saying/principle that explains why a hammer and a screwdriver, both made of steel, are used for different tasks?

Mike walks 100 meter north, then walks 30 meters south. after this, he walks another 10 meters north. what is the magnitude of his total displacement during this walk,in meters?

Explain vector addition, triangle method and parallelogram method

What must be the same for any two resistors that are connected in series ? a. the potntial diffrence across each b. the rate at which charge moves through each c. the rate at which energy is used by each d. the resistance to the flow of charge of each