ROTATIONAL MOTION

What is the primary reason for using k̂ in torque and angular momentum expressions?

• To reduce magnitude
• To indicate radial direction
• To indicate direction along the fixed axis
• To cancel perpendicular components

What is the time derivative of Lz when torque is applied?

• Zero
• Equal to I
• Equal to ω
• Equal to τ

What determines whether Lz can replace total L in calculations?

• Mass of the body
• Speed of rotation
• Symmetry of the body
• Length of the axis

What is the effect of pulling arms in on a rotating chair?

• Angular speed decreases
• Moment of inertia increases
• Angular speed increases
• Kinetic energy decreases

What is the rotational analog of Newton’s second law for fixed-axis systems?

• F = mv
• P = Fv
• τ = Iω
• τ = Iα