1. Uniform Circular Motion

2. Answer Me!!!!  Newton’s Laws state that an object in motion will stay at the same velocity until acted upon by an unbalanced force. What will happen when a force is directed perpendicular to the line of motion?

3. Uniform Circular Motion  The motion of an object at a constant speed in a circular path is call Circular Motion.  Centripetal Force is directed toward the center of the circle. This causes the object to accelerate inward toward the center. FcFc v acac

4. Centripetal Acceleration  Centripetal Acceleration (a c ) is the acceleration of an object causing the object to change direction along a circular path.  The equation that determines centripetal acceleration is: v= velocity r= radius

5. Centripetal Force  Using the equation:  Applying the centripetal acceleration:

6. Practice Problem 1  A 2000 kg car travels at a constant speed of 12 m/s around a circular curve of radius 30 m. What is the magnitude of the centripetal acceleration of the car? As the car goes around the curve, in which direction is the centripetal force directed?

7. Practice Problem 2  An athlete in a hammer-throw event throws a 7kg hammer in a horizontal circle at a constant speed of 12 m/s. The radius of the hammer’s path is 2 m. If the hammer is released, which direction will the hammer go? Straight Ahead Toward the center of the circle Along the Circular path

8. Practice Problem 3  A 1.5 kg cart travels in a horizontal circle of radius 2.4 m at a constant speed of 4.0 m/s. Draw a diagram of this motion and label the velocity, acceleration and force acting on the cart.

9. Practice Problem 4  A 60kg car travels clockwise in a horizontal circle of radius 10m at 5.0m/s. What is the magnitude of the centripetal force?

10. Practice Problem 5  A child is riding on a merry-go-round. As the speed of the merry-go-round is doubled, what happens to the magnitude of the centripetal force acting on the child?

11. Answer Me!!!  A 600kg race car travels at a constant speed along a circular race track. If it takes 36 seconds to complete one lap and the radius of the track is 160m. Calculate the speed of the car.