Question

A boy drags a box across the room with a strap at an angle of 25 degrees above the horizontal. The boy exerts a force of 10 N. If the mass of the box is 3 kg and the coefficient of kinetic friction is 0.1, what is the acceleration of the box?

Answer 1

II Newton's law for the box:
ma = F cos (25) - μ mg;
a = F/m cos(25) - μ g = 10/3 *cos(25) - 0.1*10 = 2.02 m/s²