Which substance(s) will sink if placed in a fluid that has a density of 1.19 g/ml? (List all)

Given the position vector of the particle r(t)=(t+1)i+(t^2−1)j+2t k, find the particle's velocity and acceleration vectors at t=1

Although longitudinal waves can travel through all media types what is the disadvantage of this type of wave transmission? a) he efficiency of he wave transmission is greatly diminished as the media becomes less dense b) the oscillation of one set of particles has a huge impact on neighboring particles c) particles become too close together as they bump into each other making it more likely to hit other particles down the line

Under the action of a constant force an object accelerates at 7.8 m/s2. what will the acceleration be if (a) the force is halved? (b) the object's mass is halved? (c) the force and the object's mass are both halved? (d) the force is halved and the object's mass is doubled?