Question

You push a 2 kg shopping mall cart down an aisle (how the heck is “aisle” pronounced “aiyo”). The cart is initially travelling at 5 m/s the moment it left your hand. A) What is the initial kinetic energy of the cart? The cart slowed to a complete stop due to friction. B) What is the final kinetic energy of the cart when it stopped? C) Then, use the work-energy theorem to find the work done by friction. D) If the cart travelled a distance of 10 m, what is the magnitude of the friction force? E) If the cart was moving on a flat, levelled surface, use your answer for D and the mass of the cart to find the coefficient of kinetic friction. (round all answers to 3 sig fig)

A) 25
B) 0
C) -25
D) ?
E) 0.127

Answer 1

(A) KE; = { mu? = {(2)(5) 2 KEi= 25 J 2 (B) KE} = { mu? = {(2)(0) Kef = 0J (C) W - ДКЕ - Keg-KE; Wf 0 - 25 Wp = -25 J (0) -25 Wf =-fs = -f(10) f = 2.5 N + (E) f = ung 2.5 = M (2) (9.8) M = 0.127