The equation Bold r (t )r(t)equals=(6 Bold sin t )Bold i plus (6 Bold cos t )Bold j plus (3 t )Bold k(6 sin t) i+(6 cos t) j+(3t) k is the position of a particle in space at time t. Find the particle's velocity and acceleration vectors. Then write the particle's velocity at t equals StartFraction 3 pi Over 2 EndFractiont= 3π 2 as a product of its speed and direction

Glass has a hardness that is in the middle of the hardness scale. what is the hardness of glass?

Aspring is used to stop a 50-kg package which is moving down a 20º incline. the spring has a constant k = 30 kn/m and is held by cables so that it is initially compressed 50 mm. knowing that the velocity of the package is 2 m/s when it is 8 m from the spring and neglecting friction, determine the maximum additional deformation of the spring in bringing the package to rest.

Two solutions of the same uv-absorbing molecule were analyzed by uv-vis spectroscopy on the same instrument using 1 cm pathlength cells. use data from the table to calculate by what percentage the concentration of solution b is compared to that of solution a.sample absorbance at 315nm a 0.45 b 0.80