Two identical blocks are stacked on top of each other and placed on a table. To overcome the force of static friction, a force of $10\ \mathrm{N}$ is required. If the blocks were placed side by side and pushed as shown in the figure above, how much force would be required to move them?
A) $\displaystyle \frac{10\sqrt{2}}{2\ \mathrm{N}}$
B) $10\ \mathrm{N}$
C) $10\sqrt{2}\ \mathrm{N}$
D) $20\ \mathrm{N}$
A) $\displaystyle \frac{10\sqrt{2}}{2\ \mathrm{N}}$
B) $10\ \mathrm{N}$
C) $10\sqrt{2}\ \mathrm{N}$
D) $20\ \mathrm{N}$
The force of static friction will be
$$F_{\mathrm{f}}=\mu F_{\mathrm{N}}$$
$$F_{\mathrm{f}}=\mu (mg)$$
Changing the arrangement of the blocks does not change any of these three quantities, so the force will remain the same. Thus, $10\ \mathrm{N}$ will again be required to move them.