Question

1. three blocks are pushed along a rough surface by a force with magnitude p, as shown below.

(diagram of three blocks: block 1, block 2, block 3 on a rough surface, with force p pushing block 1 from the left)

$f_c$ is the magnitude of the contact force between blocks 2 and 1, and $f_f$, $f_n$, and $f_g$ are the magnitudes of the friction, normal, and gravitational forces on block 1, respectively. which of the following is a correct free - body diagram for block 1?

(options a, b, c, d show different free - body diagrams with forces $f_n$ (upward), $f_g$ (downward), $f_c$, $f_f$, and $p$ in different directions)

Explanation:

Block 3 is pushed by Block 2, so it has a rightward contact force $F_C$. On the rough surface, kinetic friction $F_f$ acts leftward (opposing motion). Vertically, upward normal force $F_N$ balances downward gravitational force $F_G$. Option c includes all these correct forces.

Answer:

c. The free-body diagram with upward $F_N$, downward $F_G$, leftward $F_f$, and rightward $F_C$