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Acceleration in circular motion is directed towards the centre of the circle and is called centripetal acceleration.
When an object moves in a circular path, even if its speed remains constant, its velocity is continuously changing direction. Velocity is a vector quantity, meaning it has both magnitude (speed) and direction. Since the direction of the velocity is changing, the object is accelerating. This acceleration is always directed towards the centre of the circle, and it is known as centripetal acceleration.
Centripetal acceleration is crucial for maintaining circular motion. Without it, the object would move off in a straight line due to inertia, as described by Newton's First Law of Motion. The formula for centripetal acceleration is \( a_c = \frac{v^2}{r} \), where \( v \) is the speed of the object and \( r \) is the radius of the circular path. This equation shows that centripetal acceleration increases with the square of the speed and decreases as the radius of the circle increases.
In practical terms, think of a car turning around a bend. The friction between the tyres and the road provides the centripetal force needed to keep the car moving in a curved path. If the road is icy and friction is reduced, the car may not be able to generate enough centripetal force, causing it to skid outwards.
Another example is a satellite orbiting Earth. The gravitational pull of the Earth provides the centripetal force that keeps the satellite in its circular orbit. If this force were to disappear, the satellite would fly off in a straight line into space.
Understanding centripetal acceleration helps us analyse various real-world scenarios involving circular motion, from amusement park rides to planetary orbits, making it a fundamental concept in physics.
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