The position of an object that is oscillating on an ideal spring is given by the equation x = (0.1 m) cos[(1.26s-1)t]. at time t = 0.8 s, what is the magnitude of the acceleration of the object?

Atank has a shape of a cone with a radius at the top of 2 m and a height of 5 m. the tank also has a 1 m spout at the top of the tank. the tank is filled with water up to a height of 2 m. find the work needed to pump all the water out the top of the spout. (use 9.8 m/s2 for g and the fact that the density of water is 1000 kg/m3.)