X leaves his house facing west, drives 100 km, then turns right and drives 100 km. He then turns left and drives 50 km. In which direction is X facing in relation to his starting point?
________________ refers to the superposing of two or more coherent waves to produce regions of maxima and minima in space, according to the principle of superposition.
If the acceleration due to gravity on the surface of earth is g, then the acceleration due to gravity on the surface of a planet whose mass is double that of earth and radius is same as that of earth is _________________.