A box of mass 27 kg is in the bed of a truck on a hill that is inclined at an angle of 26.1° above the horizontal. The tailgate of the truck is open. The truck is currently accelerating up the hill with a magnitude of 1.67 m/s2

The truck is now at rest on the hill. If the driver guns the engine so that the truck has an acceleration of 2.81 m/s2 up the hill, then find the acceleration of the box with respect to the (essentially) inertial frame of the earth. Use 0.24 as the coefficient of kinetic friction between the box and the truck.