- #1

trolling

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Two wooden crates rest on top of one another. The smaller top crate has a mass of m1 = 24.0 kg and the larger bottom crate has a mass of m2 = 86.0 kg. There is NO friction between the crate and the floor, but the coefficient of static friction between the two crates is μs = 0.8 and the coefficient of kinetic friction between the two crates is μk = 0.63. A massless rope is attached to the lower crate to pull it horizontally to the right (which should be considered the positive direction for this problem).

The tension is increased in the rope to 1122.0 N causing the boxes to accelerate faster and the top box to begin sliding. What is the acceleration of the upper crate?

2. Homework Equations

Fg = Fn = m*g

Fk = μk * Fn

Fnet,x = T-Fk

3. The Attempt at a Solution

Fg = 24*9.8 = 235.2N

Fn = 235.2N

Fk = .63 * Fn = 148.176N

T = 1122N

Fnet,x = 1122-148.176 = 973.824N

acceleration in x-direction = 973.824/24 = 40.576 m/s^2 <- seems to be incorrect