Levers and the Principle of Moments

Try these questions

5 questions from this lesson’s quiz. Start the lesson to answer them and see the right answers.

1. 1. A farmer in Nakuru uses a wheelbarrow to carry soil. The wheel axle is the pivot, the soil sits in the tray and the farmer lifts at the handles. Which class of lever is a wheelbarrow?

   • A. First class lever
   • B. Second class lever
   • C. Third class lever
   • D. It is not a lever

2. 2. A learner pushes on a spanner with a force of 40 N. The force acts at a perpendicular distance of 0.35 m from the nut. Calculate the moment of the force about the nut.

   Type your answer (in N·m) in the lesson.

3. 3. A uniform metre rule is balanced at its centre. A 30 N weight hangs 0.4 m to the left of the pivot. A 20 N weight is hung on the right to make the rule balance. How far from the pivot, in metres, must the 20 N weight be placed?

   Type your answer (in m) in the lesson.

4. 4. What is the name given to the fixed point about which a lever turns?

   Type your answer in the lesson.

5. 5. A builder uses a 2.0 m crowbar to prize up a heavy stone. The fulcrum is 0.4 m from the stone, and the stone exerts a load of 800 N. What effort is needed to just lift the stone?

   • A. 200 N
   • B. 400 N
   • C. 160 N
   • D. 640 N

More in Energy, Work, Power and Machines

• ▸Concept and Measurement of Work
• ▸Power and the Rate of Doing Work
• ▸Introduction to Machines, Mechanical Advantage and Velocity Ratio
• ▸Machine Efficiency and Energy Losses
• ▸Pulleys and Pulley Belt Systems
• ▸Inclined Planes, Wedges and Screws
• ▸Wheel, Gears and Hydraulics
• ▸Modern Complex Machines and Technological Evolution

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