ROTATIONAL MOTION

How does the center of mass concept help in space missions?

• It reduces fuel
• It increases speed
• It allows prediction of spacecraft motion despite internal changes
• It changes gravity

What is the relationship between the velocities of two decay products in the CM frame?

• Same direction, same speed
• Opposite directions, same speed
• Velocities are in opposite directions and inversely proportional to masses
• Perpendicular directions

In Fig. 6.14(b), what is the motion of star S1?

• Moving in a straight line
• Accelerating outward
• Circular orbit about the center of mass
• At rest

Why is the center of mass motion unaffected by internal rearrangements?

• Because energy is conserved
• Because mass is fixed
• Because internal forces sum to zero net force on the system
• Because time is constant

What is the effect of choosing a different reference frame on physical laws?

• Laws change
• Trajectories are always the same
• The laws remain the same, but trajectories may look different
• Forces disappear