A student decides to move a box of books into her dormitory room by pulling on a

Question

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 150 N at an angle of 27.0° above the horizontal. The box has a mass of 20.0 kg, and the coefficient of kinetic friction between box and floor is 0.300. (a) Find the acceleration of the box. Incorrect: Your answer is incorrect. Your response is within 10% of the correct value. This may be due to roundoff error, or you could have a mistake in your calculation. Carry out all intermediate results to at least four-digit accuracy to minimize roundoff error. m/s2 (b) The student now starts moving the box up a 10.0° incline, keeping her 150 N force directed at 27.0° above the line of the incline. If the coefficient of friction is unchanged, what is the new acceleration of the box? m/s2, up the incline

Explanation / Answer

a) N = mg - Fsin27 = 20 x 9.8 - 150sin27 = 127.90 N

ma = Fcos27 - u.N

a = 4.76 m/s2

b) N = mgcos10 - Fsin27 = 124.92 N

ma = Fcos27 - mgsin10 - u.N   

20a = 150cos27 - 20 x 9.8 x sin10 - 0.3 x124.92 = 3.11 m/s2

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.