ROTATIONAL MOTION

What is the formula for the moment of a couple as derived in the text?

• r₁ × F
• r₂ × F
• (r₁ + r₂) × F
• AB × F

In the principle of moments, which direction of moment is conventionally taken as positive?

• Clockwise
• Vertical
• Horizontal
• Anticlockwise

What is the direction of the reaction force in a lever system?

• Same as the load
• Same as the effort
• Perpendicular to the lever
• Opposite to the applied forces

What is the role of the Earth's magnetic field on a compass needle according to the text?

• It attracts the needle to the north
• It creates friction
• It heats the needle
• It applies a couple to align the needle

Why is the moment of the reaction force at the fulcrum zero?

• Because the force is too small
• Because it is horizontal
• Because it cancels out
• Because the distance from the fulcrum is zero