ROTATIONAL MOTION

How does the law of conservation of linear momentum apply to an exploding projectile?

• Momentum is lost due to heat and sound
• Each fragment has more momentum than the original
• The explosion creates new momentum
• The total momentum before and after the explosion remains the same

What happens to the velocity of the center of mass if the net external force on a system is zero?

• It gradually decreases
• It increases indefinitely
• It changes direction randomly
• It remains constant

Why do internal forces not affect the motion of the center of mass?

• They are too weak to have any effect
• They only act for a short time
• They are not real forces
• They occur in action-reaction pairs and cancel each other out

What does Eq. (6.17), dP/dt = F_ext, signify in the context of a system of particles?

• Momentum is always zero in isolated systems
• Internal forces can change total momentum
• The center of mass never moves
• The rate of change of total momentum equals the net external force

How is the total linear momentum of a system of particles mathematically expressed?

• P = (m₁ + m₂ + ... + mₙ)(v₁ + v₂ + ... + vₙ)
• P = average velocity × smallest mass
• P = sum of masses divided by sum of velocities
• P = m₁v₁ + m₂v₂ + ... + mₙvₙ