Answer:
50 N.
Explanation:
On top of a horizontal surface, the normal force acting on an object is equivalent to the force of gravity acting on the object. That is:
[tex]\displaystyle \begin{aligned} F_N = F_g & = ma \\ & = mg\end{aligned}[/tex]
The mass of the block is 5 kg and the given force due to gravity is 10 N/kg. Substitute and evaluate:
[tex]\displaystyle F_N = F_g = (5\text{ kg})(10 \text{ N/kg}) = 50 \text{ N}[/tex]
In conclusion, the normal force acting on the block is 50 N.