Question

give reason if you are both on the Moon your friend will not be able to hear your call

Answer 1

Sound is a longitudinal wave sometimes in special cases it do behaves as both..
But sound waves are mechanical in nature they need medium to travel on the moon due to its very light atmosphere. And almost zero medium and atmosphere it is very difficult to hear any sound ..thus sound can't be heard on the moon

Answer 2

This is because sound needs a material medium.In case of moon , there is no material medium on the surface of moon .So , sound doesn't propagate there and you don't hear your friend's call.

Hope it helps!