1. Week

2.  Student will: centripetal accelerationcentripetal force  Solve problems involving centripetal acceleration and centripetal force

3. Centripetal Acceleration Centripetal Acceleration: The rate of change in the direction of a moving object.  An object has constant speed but is accelerating because of change in direction.  The units for centripetal acceleration (m/s 2 ) Formula: m/s 2 Centripetal Accel. (m/s 2 ) m/s Tangential Velocity (m/s) m Radius (m) Questions 1)How would you define centripetal acceleration?

4. V t : Tangential velocitytangent V t : Tangential velocity. Velocity’s direction is tangent to the circular motion.  The object’s speed along an imaginary line drawn tangent to the circular path. Example 2)What is the difference between tangential velocity and tangential speed? 3)What is the direction of centripetal acceleration? uniform circular motion When tangential speed is constant, the motion is called uniform circular motion Acceleration’s direction is always towards the center of the circle or curve.

5. Centripetal Force: Centripetal Force: The net force on an object in uniform circular motion  Friction between a car’s tires and a circular track  Gravitational force is a centripetal force that keeps the moon in its orbit. Formula: N Centripetal Force (N) kg Mass (kg) m/s Tang. Velocity (m/s) m Radius (m) 4)How would you define centripetal force?

6. Example: Centripetal Acceleration The thunder God, Thor, flies around Earth with a tangential speed of 343 m/s around Earth. If the radius of Earth is 6,371 km, what is Thor’s centripetal acceleration? Assume his mass to be 290.299 kg

7. Given: Unknown: Steps 1)Define The thunder God, Thor, flies around Earth with a tangential speed of 343 m/s around Earth. If the radius of Earth is 6,371 km, what is Thor’s centripetal acceleration? Assume his mass to be 290.299 kg

8. Choose an equation or situation: Rearrange the equation to isolate the unknown: 2)Plan

9. Substitute the values into the equation and solve 3)Calculate

10. 4)Evaluate Compare to the radius of the Earth and Thor’s velocity, the centripetal acceleration should be a small number. Thor’s centripetal acceleration is 0.0185 m/s 2 What is Thor’s centripetal force then? Extension F c = ma c