Question

A block of mass 20 kg is lying on a horizontal surface. The normal reaction force acting on the
block.
(a) 20 N
(b) 100 N
(c) 200 N​

Answer 1

Explanation:

20×10=200

because,the value of 1kg is approximately 10N

Answer 2

Given:

A block of mass 20 kg is lying on a horizontal surface.

To find:

Normal reaction on block ?

Calculation:

• When the object is placed on a horizontal surface , the object is exerting its weight on the surface.

• As per NEWTON'S 3RD LAW, each action has its equal and opposite reaction.

• So, the object also experiences an equal normal reaction in the opposite direction.

$\therefore \: N = mg$

$\implies \: N = 20 \times 10$

$\implies \: N = 20 \: Newton$

So, normal reaction is 20 N.