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002 (part 1 of 2) 10.0 points A student decides to move a box of books into her

ID: 1539369 • Letter: 0

Question

002 (part 1 of 2) 10.0 points A student decides to move a box of books into her dormitory room by pulling on a rope at- tached to the box. She pulls with a force of 160 N at an angle of 29° above the horizon- tal. The box has a mass of 26.2 kg, and the coefficient of friction between box and floor is 0.262. 2 N 160 The acceleration of gravity is9.8 m/s 26.2 kg 0.262 Find the acceleration of the box. Answer in units of m/s 003 (part 2 of 2) 10.0 points The student now starts moving the box up a 13.40 incline, keeping her 160 N force directed at 29f above the line of the incline. 26.2 kg 13.45 If the coefficient of friction is unchanged.

Explanation / Answer


F =160 N , m = 26.2 kg, uk = 0.262 , g = 9.8 m/s^2

Net force along vertical direction

N +Fsin(29) = mg

N +160*sin(29) = 26.2*9.8

N = 179.2 N

Net force along horizontal direction

Fcos(29) -Fk = ma

Fk = uk*N

160*cos(29) - 0.262*179.2 = 26.2*a

a = 3.55 m/s^2


Net force along vertical direction

N +Fsin(29+13.4) = mgcos(13.4)

N +160*sin(29) = 26.2*9.8cos(13.4)

N =172.2 N

Net force along horizontal direction

Fcos(29+13.4) -Fk -mgsin(13.4) = ma

160*cos(29+13.4) - 0.262*172.2 - 26.2*9.8*sin(13.4) = 26.2*a

a = 0.52 m/s^2