Which class of lever?

Straightening the elbow: the triceps pulls up behind the elbow, the hand’s load lies in front

Nodding the head: neck muscles pull down behind the skull, the face’s weight lies in front of the joint on the spine

Kicking a ball: the quadriceps pulls on the shin just below the knee, the foot far out

A biceps curl: the biceps pulls just past the elbow, the weight is held in the hand

Tweezers: hinged at one end, squeezed in the middle, gripping at the tips

Scissors: the pivot between the handles and the blades

A wheelbarrow: the wheel at one end, the load in the middle, the handles lifted

Rising on tiptoe: the calf pulls up at the heel, the body’s weight presses down at the ankle, the ball of the foot pivots