GED Science TestPhysical ScienceMedium
A satellite orbits Earth in a circular path at a constant speed. Despite its constant speed, the satellite is continuously accelerating. This acceleration is directed towards the center of the Earth and is responsible for keeping the satellite in orbit. What type of force is responsible for this acceleration?
- AFrictional force.
- BCentripetal force.
- CNormal force.
- DTangential force.
Show answer & explanationAnswer & explanation
Correct answer: B. Centripetal force.
An object moving in a circular path at constant speed still undergoes acceleration because its direction of velocity is constantly changing. This acceleration is called centripetal acceleration, and the force causing it is centripetal force, which acts towards the center of the circle (in this case, the Earth).
Why the other options are wrong
- A. Frictional force typically opposes motion or prevents sliding; it is not the primary force for orbital motion.
- C. Normal force acts perpendicular to a surface; it's not relevant for an orbiting satellite.
- D. Tangential force would change the speed of the satellite, not keep it in a circular path.
Centripetal Force
A center-seeking force that acts on an object moving in a circular path, causing it to accelerate towards the center of the circle and maintain its circular motion.
- Always directed towards the center of the circular path.
- Responsible for centripetal acceleration.
- Examples: tension in a string, gravitational force, friction on a turning car.
Memory trick: Centripetal 'pulls to the Center'.