7. Rotational motion

Question 1

What is the moment of inertia?

Answer 1

How easy it is to change the rotational velocity of an object.

Question 2

Moment of inertia is directly proportional to what?

Answer 2

The mass and radius squared of an object’s distance from the axis of rotation.

Question 3

Torque is similar to concepts of what?

Answer 3

Force, except for objects in rotation.

Question 4

Torque is directly proportional to what?

Answer 4

force, the length of the arm, and the sine of the angle between the force and lever arm.

Question 5

Counterclockwise torque is what?

Answer 5

Positive.

Question 6

Newton’s second law states that a nonzero net torque will rotationally what?

Answer 6

Accelerate an object.

Question 7

The torque of an object in rotational motion is directly proportional to what?

Answer 7

Moment of inertia and angular acceleration.

Question 8

Angular velocity is similar to what other concept, except for objects in rotation?

Answer 8

Velocity.

Question 9

What is angular velocity directly proportional to?

Answer 9

Angular displacement.

Question 10

How many kinematic equations of rotation are there?

Answer 10

4.

Question 11

How many rotational kinematic variable are there?

Answer 11

5. And if you know any 3, you can solve for the 2 unknown variables.

Question 12

An object’s angular acceleration is directly proportional to the change in what?

Answer 12

Angular velocity.

Question 13

What is the direction of angular acceleration?

Answer 13

Along the axis of rotation.

Question 14

Answer 14

Question 15

Answer 15

Centripetal

Question 16

If a particle moves in a plane so that its position is described by the functions
x = A cos ωt and y = A sin ωt, the particle is doing what?

Answer 16

Moving with constant speed along a circle.

Question 17

The rate at which a rotating object spins, its angular velocity, can be expressed in all of the following ways except

• degrees/sec.
• rotations/sec.
• rad/sec.
• rpm.
• revolutions/sec.

Answer 17

revolutions/sec.

Question 18

A wind turbine, with 4m long blades, turns at a rotor speed of 2.9rad/3s. What is the linear velocity of the tip of the blade?

Answer 18

Question 19

Jupiter has the fastest rotation of all the planets in the Solar System, completing one rotation on its axis every 9.9 hours. The rapid rotation causes the planet’s equator to bulge out. Instead of being a perfect sphere, Jupiter looks more like a squashed ball. What is its angular velocity in radians per second?

Answer 19

Question 20

Answer 20