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1. A student decides to move a box of books into her dormitory room by pulling o

ID: 1967207 • Letter: 1

Question

1. A student decides to move a box of books into her dormitory room by pulling on a rope attached to the box. She pulls with a force of 117.0 N at an angle of 16.0° above the horizontal. The box has a mass of 25.0 kg, and the coefficient of kinetic friction between box and floor is 0.300.

(a) Find the acceleration of the box.
_____m/s2
(b) The student now starts moving the box up a 10.0° incline, keeping her 117.0 N force directed at 16.0° above the line of the incline. If the coefficient of friction is unchanged, what is the new acceleration of the box?
Magnitude
_____m/s^2 Direction up the incline

Explanation / Answer

Fnet= 117Cos(16)-(25*9.8*0.3)=112.4676-73.5=38.9676N Fnet= ma a=Fnet/m=38.9676/25=1.5587 m/s^2 Fnet= 117Cos(16)-[0.3*mg Cos(10)]-[mg sin(10)]=112.4676-72.383369-42.5438= =-2.459555m/s^2 a=-2.459555/25=-0.09838 the magnitude is: 0.09838 m/s^2