Question

At the beginning of a new school term, a student moves a box of books by attaching a rope to the box and pulling with a force of F = 84.4 N at an angle of 64degrees. The acceleration of gravity is 9.8 m/s/s. The box of books has a mass of 14 kg and the coefficient of kinetic friction between the bottom of the box and the floor is 0.3. whats the acceleration of the box? Answer in units m/s/s

Answer 1

force upward: F= 84.4sin64
force normal on floor= bookweight-Fup
= 14*9.8-84.4sin64

friction= mu(forcenormal)

force horizontal= 84.4cosTheta

F=ma
84.4cosTheta-mu(forcenormal)*a
solve for a.

Answer 2

3