In other words, the hand will be both pulled and twisted when the ball hits the racquet. These resultant forces from impact should be minimized. In some modern handbooks and textbooks, the center of percussion, which was prominent in earlier books, has been given hardly any consideration, so modern-day students may have a blind spot in their education. The axis of rotation is 7 cm from the handle end on the forehand, and 5 cm on the serve. So you see that the Sweet Spot can shift according to where you hold the racquet.
Weight is a force.
Weight is the product of an object's mass and the acceleration due to gravity. Acceleration of the mass center downward due to gravity results in a force acting at the balance point. The axis of rotation on the forehand is 7 cm from the handle end. Moment is a measure of how heavy the racquet feels when you hold it parallel to the ground. A head-heavy racquet will have a high Moment, which is bad not only because it tires the arm but also because it aggravates the twist on the arm from shots off the centerline of the racquet.