Forces at work during circular motion The diagram below shows an object, travelling at a constant speed, at two different points along its circular path. Real life examples of this could be the Moon orbiting the Earth, or a car driving around a circular track.  |
Though its speed stays the same, the object's direction and therefore velocity are constantly changing. Since velocity is changing, the object must be accelerating even though its speed does not change. This acceleration happens because a force acts on the object, pointing toward the centre of the circle. This force, known as centripetal force, causes the object to change direction, accelerating the object perpendicular to its motion. A centripetal force is required to maintain circular motion at constant speed. |
Key points to understand for objects undergoing circular motion:
|
Varying circular motion
The centripetal force responsible for circular motion is dependent on the mass, speed, and radius of the orbit.
Mass:
Increasing the mass would increase the centripetal force required to keep the object travelling at the same speed with the same radius.
Speed:
Increasing the speed would increase the centripetal force required to keep the object travelling with the same radius and mass.
Orbital radius:
Increasing the radius of orbit would decrease the centripetal force required to keep the object travelling at the same speed.
Which force is responsible for the acceleration of an object in circular motion?
Gravitational force
Electromagnetic force
Centripetal force
Frictional force
|
Which factor does not affect the circular motion of an object?
Speed of the object
Mass of the object
Radius of the object
Radius of the circular path
|
What happens to the centripetal force required to keep an object at a constant speed if the mass of the object is increased?
The centripetal force remains the same
The centripetal force increases
The centripetal force decreases
The centripetal force becomes zero
|
What happens to the speed of an object traveling in a circular path if the centripetal force is increased?
The speed remains the same
The speed increases
The speed becomes zero
The speed decreases
|
What is the term for the force that acts perpendicular to the direction of motion, towards the center of a circle in circular motion?
|