ROTATIONAL MOTION

What is the vector form of torque in rotation about a fixed axis?

• τî
• τĵ
• τk̂
• τr̂

Can angular momentum be conserved even if kinetic energy changes?

• No, both must be conserved
• Yes, because internal forces can change energy
• Only in vacuum
• Only for rigid bodies

What happens to angular momentum when a torque is applied opposite to rotation?

• It increases
• It remains same
• It becomes zero
• It decreases

How is angular momentum conserved in planetary motion?

• By changing speed
• Through constant areal velocity
• By elliptical path
• By gravity

What is the vector sum of Lz and L⊥?

• Net torque
• Linear momentum
• Kinetic energy
• Total angular momentum L