Final answer:
The equation 1/2(m*v_f^2) - 1/2(m*v_i^2) represents the change in kinetic energy rather than average force. To calculate average force, the change in momentum should be divided by the time interval over which the force was applied.
Step-by-step explanation:
The equation 1/2(m*v_f^2) - 1/2(m*v_i^2) represents the change in kinetic energy, not the average force. To find the average force, you need to consider the time interval during which the force was applied. You can calculate the change in momentum, m△v = mv_1 = m√/2ghdrop, and divide by the time interval to find the average force. This method is known as impulse and involves the principles of momentum conservation.
In the context of a tennis ball being struck by a racquet, as in the example of Venus Williams, the average force exerted by the racquet on the ball can be determined by finding the change in momentum (caused by the racquet) over the time of impact. Gravity also acts on the ball during this time, but it is a separate force that is not due to the racquet.