A feather of mass 15 g is dropped from a height. It is found to fall with a constant velocity. What is the net force acting on it?

The tendency of an object to resist a change in its state of motion is called:

A box of mass 15 kg is kept on the floor of a stationary trolley. The coefficient of static friction between the box and the trolley is 0.12. To keep the box stationary relative to the trolley, the maximum horizontal acceleration (in m/s2) with which the trolley can move is: (g = 10 m/s2)