Question

give reason why we can easily move our hand in air but to do the same through a solid block of wood we need a Karate expert

Answer 1

the weight is pulling down by gravity so our hand can't hold it that's why we need karate expert because they have better strength than us and they also have tricks for this

Answer 2

it is because in air the intermolecular space is very high
in solid the inter molecular space is almost nil
that is why we can move our hand through air easily than solid