A plane needs to reach a velocity of 300 km/h relative to the air in order to take off. There is a wind blowing at 80 km/h in the direction opposite to take off. What velocity must the plane reach relative to ground in order to take off?

energy can be converted from one form to another, but it cannot be created or destroyed in ordinary chemical or physical means. do not understand what you are asking but hope this

one person pulls 90n one way and the other has 100n pulling the other way.

so the net force = 90 - 100 = -10n,

or the ans can be 10n if the picture shows -90n and 100n instead.

if the person is shown to have +90n, then ans is -10n.

if the person is shown to have -90n, then ans is +10n.