At the beginning of a new school term, a

Question

student moves a box of books by attaching a
rope to the box and pulling with a force of
F = 88.9 N at an angle of 56◦
, as shown in the
figure.
The acceleration of gravity is 9.8 m/s
2
.
The box of books has a mass of 17 kg and
the coefficient of kinetic friction between the
bottom of the box and the floor is 0.24.

Answer 1

M*g = 17kg * 9.8N./kg = 166.6 N. = Wt. of box.

Fn = 166.6 - 88.9*sin56 = 92.9 N. = Normal force.

Fk = u*Fn = 0.24 * 92.9 = 22.3 N. = Force of kinetic friction.

a = (F*Cos A-Fk)/M =
F = 88.9 N.
A = 56o
M = 17 kg
Solve for a.