Question

7. You can probably stand flatfooted on the floor and then rise up and balance on your tiptoes. Why are you unable to do it if your toes are touching the wall of your room? (Try it!)

Short answer

The net torque at the point of balancing the whole body on the tiptoes makes us fall backward.

Step-by-step solution

Center of gravity

The center of gravity is the point on a body where the total weight of the body is concentrated.

Center of gravity on tiptoes

The center of gravity is aligned with the point of support while balancing the whole body with the tiptoes.

Here, the normal force on the fingers act in the same line of action implies the net torque is zero.

Therefore, the net torque at the point of balancing the whole body in the tiptoes makes us fall backward.