ROTATIONAL MOTION

What is the state of equilibrium when a rod accelerates linearly but does not rotate?

• Translational equilibrium only
• Complete equilibrium
• Rotational equilibrium but not translational equilibrium
• No equilibrium

What is the effect of doubling the length of a rod on the torque of a couple with the same forces?

• Torque halves
• Torque remains same
• Torque quadruples
• The torque doubles

How does the Earth's magnetic field cause a compass needle to rotate?

• By heating the needle
• By charging it electrically
• By attracting the whole needle
• By applying a couple that creates a torque until the needle aligns with the field

What is the condition for zero net torque in a two-force system on a rod?

• Forces must be zero
• Forces must be in same direction
• The torques must be equal in magnitude and opposite in direction
• Distances must be zero

What is the moment of a force about a point?

• Force divided by distance
• Mass times acceleration
• The product of the force and the perpendicular distance from the point to the line of action
• Distance divided by force