Halliday, Resnick & Walker — Force and Motion-II: Problem 26

26 Figure 6-32 shows three crates being pushed over a concrete floor by a horizontal force \(\vec{F}\) of magnitude 425 N. The masses of the crates are \(m_1 = 30.0\) kg, \(m_2 = 10.0\) kg, and \(m_3 = 20.0\) kg. The coefficient of kinetic friction between the floor and each of the crates is 0.700. (a) What is the magnitude \(F_{32}\) of the force on crate 3 from crate 2? (b) If the crates then slide onto a polished floor, where the coefficient of kinetic friction is less than 0.700, is magnitude \(F_{32}\) more than, less than, or the same as it was when the coefficient was 0.700?