Which statement best describes the role of gravity? it decreases the mass of objects. it increases the density of objects. it repels objects in proportion to their temperature. it draws objects together in proportion to their mass.

An inclined plane wrapped around a metal shaft is a a. lever b. screw c. pulley d. wedge

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".

What accounts for an increase in the temperature of a gas that is kept at constant volume? a. energy has been removed as heat from the gas. b. energy has been added as heat to the gas. c. energy has been removed as work done by the gas. d. energy has been added as work done by the gas.