Question

Find the force of interaction between $3kg$ and $2kg$ bodies in the figure shown. (Take $g=10m/s^2$)

• A. $15N$
• B. $25N$
• C. $30N$
• D. $45N$

Answer 1

The correct option is A $15N$

Taking the bodies as a single system, we can draw its FBD as

Hence, net force $=48-30=18N$ (down the plane)
$\Rightarrow a=\frac{18}{6}=3m/s^2$

Now, draw the FBD for the $3kg$ block


$3g\sin {53}^{\circ }-N_2=3a$
$\Rightarrow 24-N_2=9$
$\Rightarrow N_2=24-9=15N$