help with 4 multiple choice questions?

Question

i found all the other answers on my worksheet but i cant seem to get these:

22. Which of the following quantities measures the ability of a force to rotate or accelerate an object around an axis? a. axis of rotation, b. lever arm, c. moment arm, d. torque

28. Which of the following statements is corect? a. Wth a net positive torque, the angular acceleration of an object is clockwise, b. With a net positive torque, th angular acceleration of an object is counterclockwise, c. With a net negative torque, the angular acceleration of an object is counterclockwise, d. The net force of an object is not related to the translational acceleration given to the object.

30. The total kinetic energy of a baseball thrown with a spinning motion is a function of which of the following? a. the ball's linear speed only, b. the ball's rotational speed only, c. both the ball's linear and rotational speeds, d. neither the ball's linear nor the ball's rotational speed.

oh woops i meant 3 multiple choice questions...

but um also could someone explain me the difference between linear speed to rotational speed? or linear motion to rotational motion?

Answer 1

22-d, 28-b, 30-c

A baseball has rotation and translational motion. Torque is a measurement of the ability to produce angular acceleration, while force is related to the translational acceleration (hence 28-d is false) 28-a and 28-c are equivalent, which should have been a clue that 28-b is the right answer.

Answer 2

Hi. 22,d. 28,d. 30,c. Now go and understand why, OK? An object with linear motion (motion in a line) has linear kinetic energy. An object that has rotational motion ( rotates about an axis) has rotational kinetic energy. A thrown baseball usually has both.