Asmall block with mass 0.0400 kg is moving in the xy-plane. the net force on the block is described by the potential-energy function u(x, y) = (5.80 j/m2 ) x2 − (3.60 j/m3 ) y3 . what are the magnitude and direction of the acceleration of the block when it is at the point (x=0.300 m, y=0.600 m)? draw the acceleration vector with components, and make a sketch of the potential energy vs. x and y

Assume that a person skiing high in the mountains at an altitude of h = 15100 ft takes in the same volume of air with each breath as she does while walking at sea level. determine the ratio of the mass of oxygen inhaled for each breath at this high altitude compared to that at sea level. assume that the air composition (i.e. % of air that is oxygen) is the same at sea level as it is at 15100 ft.

Often called simply "velocity," this is the velocity of an object at a particular moment in time.

Two cannon balls weighing 18 kg and 24 kg are chained together and fired horizontally with a velocity of 165 m/s from the top of a 21-m wall. the chain breaks during the flight of the cannonballs and the 18-kg cannonball strikes the ground at t = 1.5 s, at a distance of 240 m from the foot of the wall, and 7 m to the right of the line of fire. determine the position of the other cannonball at that instant. neglect the resistance of the air.