IB Unit 4: Levers & Angular Motion

Which of the labels for the lever system are correct? Effort, Fulcrum, Load

• YZX

• ZXY

• XYZ

• YXZ

The diagram below shows an athlete performing a heel raise. Which of the labels are correct for a

second class lever? EFFORT, FULCRUM, LOAD

• YXZ

• XZY

• YZX

• ZYX

Which applies when an ice skater extends their arms and leg while spinning? MOMENT OF INERTIA, ANGULAR VELOCITY

• Increases, Decreases

• Decreases, Decreases

• Increases, Increases

• Decreases, Increases

Which of the following describes a third class lever?

I. Effort force acts between the fulcrum and the load force.

II. Load force acts between the fulcrum and the effort force.

III. Fulcrum is between the load force and the effort force.

• I only

• II only

• III only

• I, II and III

What is the centre of mass of a body?

• The geometric centre of the body

• The average weight between the appendicular and axial skeletons

• The point equidistant between the navel and the third lumbar vertebrae

• The point at which the mass and weight of a body/object are balanced in all directions

Which type of lever is used in plantar flexion?

• First

• Second

• Third

• No lever is used in plantar flexion

The diagram shows the operation of a lever when rising up on the toes. What part of the lever is

labelled X?

• Fulcrum

• Effort

• Load

• Resistance

What is the relationship between angular momentum, angular velocity and moment of inertia?

• Moment of inertia = angular velocity × angular momentum

• Angular momentum = angular velocity ÷ moment of inertia

• Angular velocity = moment of inertia ÷ angular momentum

• Angular momentum = angular velocity × moment of inertia

Why does a diver use the tuck position?

• To reduce spin by decreasing moment of inertia

• To reduce spin by increasing moment of inertia

• To increase spin by decreasing moment of inertia

• To increase spin by increasing moment of inertia

Which levers have the effort and the load on the same side of the fulcrum?

I. First class lever

II. Second class lever

III. Third class lever

• I and II only

• I and III only

• II and III only

• I, II and III