Question

Find contact force between 6 kg & 4 kg.

• A. 0 N
• B. 12 N
• C. 8 N
• D. 6 N

Answer 1

The correct option is A 0 N

Let's assume the bodies move with common acceleration a.
Then, $a=\frac{12+8}{6+4}=2m{s}^{-2}$
Now for the first block,
$F-N=6a\Rightarrow 12-N=12\Rightarrow N=0$