(b) Each airport has a runway that is about 500 m long.When it lands, the speed of the aeroplane is 40 m/s.Explain why the airline should not use an aeroplane that has more mass and needs a higher speed forlanding.

The reason why an airline should not use an airplane that has more mass and needs a higher speed for landing is due to the physics of motion and friction.

1. Higher Mass: An airplane with a higher mass would require more force to slow down and stop. This is due to Newton's second law of motion, which states that the force required to move an object is equal to its mass times its acceleration (F=ma). In this case, the acceleration is negative because the plane is slowing down. So, a higher mass would require a higher force to slow down, which could be problematic on a 500m runway.

2. Higher Speed: If the airplane lands at a higher speed, it would cover more distance before it can come to a stop. This is because stopping distance is directly proportional to the square of the speed at which the vehicle is traveling. So, if the speed is higher, the stopping distance would be significantly longer.

3. Runway Length: Given that the runway is only 500m long, there is a limit to how much distance is available for the plane to slow down and stop. If the plane has a higher mass and lands at a higher speed, it might not be able to stop before the end of the runway, which could lead to accidents.

Therefore, for safety reasons and to ensure that the plane can safely land and stop within the 500m runway, the airline should not use an airplane that has more mass and requires a higher speed for landing.