A spy runs from the front to the back of an aircraft carrier at a velocity of 3.4 m/s. The
aircraft carrier is moving forward at 15.0 m/s.
How fast does the spy appear to be running when viewed by an observer on a nearby
stationary submarine (forward is positive)?
Answer in units of m/s.

Could someone . i have tried to solve myself but my calculation is off

Air conditioners not only cool air, but dry it as well. suppose that a room in a home measures 5.0m×9.0m×2.4m . if the outdoor temperature is 30 ∘c and the vapor pressure of water in the air is 85 % of the vapor pressure of water at this temperature, what mass of water must be removed from the air each time the volume of air in the room is cycled through the air conditioner? the vapor pressure for water at 30 ∘c is 31.8 torr.

Which statement best describes the direction of the buoyant force on any object? a. opposite the force of gravity b. in the same direction as the weight c. in the direction of motion of the object d. opposite the direction of motion of the object