Answer:
A mechanical wave is a wave that is an oscillation of matter, and therefore transfers energy through a medium. While waves can move over long distances, the movement of the medium of transmission—the material—is limited. Therefore, the oscillating material does not move far fro
Explanation:
Here we know that mass of the person is 90 kg
His weight is given as 30 lbf
so here we can convert it into Newton as we know that
1 lbf = 4.45 N
Now from above conversion

now we can use this to find the gravity at this height



now we know that with height gravity varies as



so above is the height from the surface of earth
Newton's 3rd law:
Every action has an equal and opposite reaction.
When you apply force on an object, there is an equal force applied on you from that object.