Adhesive capsulitis, also known as a "frozen shoulder" is a condition that affects the motion of the shoulder joint. The articular shoulder capsule becomes inflamed, stiff, and restricts a person's mobility. Physical therapy provides one course of treatment for a frozen shoulder. One of the exercises often performed is the pendulum. Here, the patient bends forward and lets the injured arm hang downward and swing freely like a pendulum (see figure). The patient slowly swings their arm in a circular motion, for say 10 cycles, and then switches direction and completes 10 more. The patient may hold a light-weight dumbbell while performing this motion, or just use an empty hand. Imagine the situation shown in the drawing. A patient is moving a 7.0- Ib (3.2 kg) dumbbell at constant speed and completes one circular motion in 1.2 s. What is the radius (r) of the circular motion?

Adhesive capsulitis, also known as a "frozen shoulder" is a condition that affects the motion of the shoulder joint. The articular shoulder capsule becomes inflamed, stiff, and restricts a person's mobility. Physical therapy provides one course of treatment for a frozen shoulder. One of the exercises often performed is the pendulum. Here, the patient bends forward and lets the injured arm hang downward and swing freely like a pendulum (see figure). The patient slowly swings their arm in a circular motion, for say 10 cycles, and then switches direction and completes 10 more. The patient may hold a light-weight dumbbell while performing this motion, or just use an empty hand. Imagine the situation shown in the drawing. A patient is moving a 7.0- Ib (3.2 kg) dumbbell at constant speed and completes one circular motion in 1.2 s. What is the radius (r) of the circular motion?