The strength of the gravitational field of a source mass can be measured by the magnitude of the acceleration due to gravity at a field point. thus the gravitational field strength at a point depends on the distance from the source mass. for this problem assume that earth’s mass is concentrated at its center and that earth has a radius of re = 6,378 km at sea level and a mass of me = 5.972×1024 kg. ignore any forces due to earth’s rotation or due to other astronomical bodies.

Answer asap! the weather patterns on earth are shown in this image. explain why there are convection currents; why there are hotter and colder parts of earth.

This is important 1. what happens to the speed of molecules in water vapor when it condenses to form a liquid? (2 points) the molecules slow down. the molecules speed up. the molecules slow down and then speed up. the molecules speed up and then slow down. 2. how might human activities change to compensate for a decrease in water supplies? (2 points) humans might build a factory. humans might build drainage systems. humans might extract more water from the ground. human behavior does not change because of the water cycle. i'll be grateful if anyone can answer these 2 questions !

Aparticle's position is given by x = 3.00 - 9.00t + 3t2, in which x is in meters and t is in seconds. (a) what is its velocity at t = 1 s? (b) is it moving in the positive or negative direction of x just then? (c) what is its speed just then? (d) is the speed increasing or decreasing just then? (try answering the next two questions without further calculation.) (e) is there ever an instant when the velocity is zero? if so, give the time t; if not, answer "0". (f) is there a time after t = 3 s when the particle is moving in the negative direction of x? if so, give the time t; if not, answer "0".