Question

why are satellites placed into orbit at least 150 km above earths surface?
o to avoid air resistance
o to match earths curvature
o to create inertia
o to increase friction

Explanation:

Satellites are placed at least 150 km above Earth's surface. In the upper atmosphere (above 150 km), the air density is extremely low. Air resistance is a force that opposes the motion of an object moving through air. If satellites were placed lower (where air density is higher), air resistance would cause the satellite to lose energy (by doing work against the air resistance force) and eventually spiral down and crash into the Earth. By placing them at least 150 km above the surface, the air resistance is negligible (very small), allowing the satellite to maintain its orbit for a long - time without significant energy loss due to air - resistance - related effects.

• Option "to match Earth's curvature": Earth's curvature is a geometric property of the Earth. While satellites do orbit around a curved Earth, the main reason for the 150 km altitude is not to match the curvature but to avoid air resistance. Satellites in lower - altitude orbits (if there was no air resistance) could still follow the curvature of the Earth.
• Option "to create inertia": Inertia is a property of matter (an object's resistance to change in its state of motion). It is not created by placing a satellite at a particular altitude. All objects have inertia regardless of their position.
• Option "to increase friction": Friction (in the form of air resistance, which is a type of frictional force for objects moving through air) is something we want to minimize for satellites. Increasing friction would be counter - productive as it would cause the satellite to lose energy more quickly.

Answer:

to avoid air resistance