Figure 6-47 shows three crates being pushed over a concrete floor by a horizontal force 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?

Explanation

`(a)F_(32)=m_(3)(a+mu_(k)g)=142N,` (b) The answer here is the same as in part (b)