Circular Motion Uniform circular motion: examples include - ppt download

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Objects in orbit (earth around the sun. Driving a car around a corner. Rotating a ball around on a string.
According to Newton’s mechanics, objects don’t tend to move in a circle by themselves. They tend to either be at rest of move in a straight line at constant speed (this is Newton’s first law)
Something (a Force) must make an object move in a circle. The Force causing circular motion can be one of many different forces, depends on the situation (orbit = gravitational force, car turning a corner = frictional force between tires and the road, ball on a string = tension force)
Now gravity is influencing circular motion.
But if the object is in uniform circular motion, their speed is constant, so is acceleration = 0
In circular motion, the acceleration is a change in the direction of the object, even though the speed is constant, the direction keeps changing, and velocity is a vector. The force keeps pulling the object to the center, hence we call this type of acceleration centripetal acceleration which means center seeking .
F = ma still works, now we have a new term for centripetal acceleration. ac = v2/r acceleration (centripetal) = velocity squared/radius.
Let’s say it’s a 1 kg ball rotating at 4 m/s at a radius of 0.5m. What is the Force of tension in the string Find the acceleration of the ball where a = v2/r. Using the idea that F=ma and that the Force causing circular motion is the tension in the string.