Vocabulary Review Write the term that correctly completes the statement. Use each term once. angular acceleration angular displacement angular velocity center of mass 10. 11. centrifugal \"force" Newton's second law for . . u ,, rotational motion COrIOIIS force radian lever arm , , torque moment of Inertia Angular acceleration is directly proportional to the net torque and inversely proportional to the moment of inertia is a statement of As an object rotates, the change in angle is called The of a rotating object can be calculated by dividing its angular displacement by the time it takes for the displacement to occur. The of an object is the point on the object that moves in the same way that a point particle would move. The is the resistance to rotation. One is equal to approximately 57.3\". The apparent force that seems to pull an object on a spinning platform toward the outside of the platform is called the The result of dividing the change in angular velocity by the time it takes to make the change is is the measure of how effectively a force causes rotation. When a force is exerted on a rotating object, the change in angular velocity depends on the _, which is the perpendicular distance from the axis of rotation to the point where the force is exerted. When the horizontal motion of an object in a rotating frame of reference seems to deflect, the apparent force is the 2. Can a force of 400 N exert a greater torque than a force of 900 N? Explain your answer. 3. Henry has two batons. Baton A has identical round objects on each end. The round objects on the ends of baton B are unequal in size and mass. 3. When Henry holds each of the batons in the middle, which one has net torque equal to zero? Explain your answer. b. How can Henry hold baton B so that it has net torque equal to zero? 4. Barbara exerts a force of 48 N on the outer edge of a door that is 76 cm wide. What is the magnitude of torque if the force is perpendicular to the door? In your textbook, read about the moment of inertia. For the objects described in questions 512, write the formula you wouid use to calculate the moment of inertia. Coicuiate the moment of inertia for each. Show your coicuiotions. 5. A solid rubber ball has a radius of 32 cm and a mass of 0.85 kg with the axis of rotation through the center. Refer to the diagram at right to answer questions 17. lf the statement is true, write true. if the statement is false, rewrite the italicized part to make it true. 1. If a point on the car moving along the edge of the circle rotates from point A to point B in a counterclockwise direction, its angular displacement is positive. 2. The value of Ellis approximately 5; rod. 3. The variable r represents the distance the point moves as the circle rotates. 4. The actual distance the point travels is its angular displacement. 5. Angular displacement is measured in meters. 6. If it takes 4 s for the point to move so that 9: it, its angular velocity is % rod/s. 7. If the point is at rest at A and it has an angular velocity of sz rad/s when it reaches point B 2 5 later, it has an angular acceleration of 10% rad/52. SECTION 2 Rotational Dynamics In your textbook, read about torque and net torque. Answer the following questions. Use complete sentences. 1. Sometimes sit-ups are done with your arms out in front of you, and sometimes they are done with your hands behind your head. In terms of torque, why is it less difficult to do a sit-up with your arms out in front of you? Chapter 6 - Rotational Motion