Acompression is in a medium caused by a longitudinal wave a)region of high density b)region of low density c)region of high altitude d)region of zero pressure

The crank oa rotates in the vertical plane with a constant clockwise angular velocity ω0 of 5.6 rad/s. for the position where oa is horizontal, calculate the force under the light roller b of the 10.6-kg slender bar ab.

If steel is more dense that lake water, why can a boat float

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