How can an aircraft carrier (or a concrete canoe) float when the density of the material used to build it is greater than water?

For general projectile motion, when the projectile is at the highest point of its trajectory, its acceleration is zero? a)the horizontal and vertical components of its velocity are zero. b) its velocity is perpendicular to the acceleration. c)the horizontal component of its velocity is zero. d)its velocity and acceleration are both zero.

When an object is heated it contracts. a. true b. false

Does anyone have the answers to online physics course plato course physics, semester a v3.0