4. In a shopping mall, two elevators pass each other moving in opposite directions. Each elevator to the other is 10 m/s. What is the velocity of each elevator relative to a person standing on the ground?

Question

One elevator has a velocity of 5 m/s and the other elevator has a velocity of -5 m/s.
Both elevators have a velocity of 5 m/s.
Both elevators have a velocity of 10 m/s.
One elevator has a velocity of 10 m/s, and the other elevator has a velocity of -10 m/s.

I’m really confused on this one. Any help? If so can you explain how to get the answer and the correct answer or at least walk me through the problem and show me how to get the correct answer?

Answer 1

Hey one is going up and the other down
so one v is +
and the other v is - relative to ground
+5 - (-5) = 5+5 = 10
or equivalently
-5 - (+5) = -10
depending on which you look from :)