ROTATIONAL MOTION

What is the relationship between force and linear momentum change?

• Force equals momentum
• Force equals rate of change of linear momentum
• Force is independent
• Force equals mass times velocity

What is the implication of constant direction of angular momentum vector?

• Force is increasing
• Velocity is zero
• No external torque is acting
• Mass is changing

How is rotational equilibrium condition generalized for n forces?

• Sum of forces zero
• By vector sum of all torques being zero
• Product of forces
• Average torque zero

What is required for a rigid body to be in complete equilibrium?

• Only ΣFi = 0
• Only Στi = 0
• Either force or torque zero
• Both ΣFi = 0 and Στi = 0

If Στi = 0 about one point and ΣFi = 0, what about other points?

• Torque increases
• Only valid at center
• Στi = 0 about any point
• Torque becomes infinite