Final answer:
Elise is traveling at a speed of 96 m/s in the opposite direction relative to the other people on the airplane.
Step-by-step explanation:
Elise is walking towards the front of the plane with a speed of 4 m/s. Since the plane is moving at a speed of 100 m/s relative to the Earth, Elise's speed relative to the other people on the airplane can be found by subtracting the speed of the plane from her walking speed.
- Elise's speed relative to the other people on the airplane = Elise's walking speed - Plane's speed
- Elise's speed relative to the other people on the airplane = 4 m/s - 100 m/s
- Elise's speed relative to the other people on the airplane = -96 m/s
Therefore, Elise is traveling at a speed of 96 m/s in the opposite direction relative to the other people on the airplane.