Final answer:
When a basketball player jumps, the force exerted on the floor is greater than her weight to allow for upward acceleration. This situation can be analyzed through energy considerations and Newton's Second Law of Motion.
Step-by-step explanation:
When the basketball player crouches and jumps straight up by rapidly extending her legs, the force of her feet on the floor is more than her weight. This is because in order to accelerate upwards against gravity and achieve liftoff, the player must exert a force greater than the force of gravity acting downwards on her mass. In physics, this is analyzed using the concept of Newton's Second Law of Motion, which states that the force exerted on an object is equal to the mass of the object multiplied by the acceleration (F = ma). Since the acceleration needed to jump includes both overcoming the force of gravity and providing additional upward velocity, the force exerted must necessarily be greater than the player's weight (which is the force due to gravity alone).
To calculate the velocity when the player leaves the floor, we would use energy considerations, comparing the potential energy at the height of the jump with the kinetic energy at the point of takeoff. Average force exerted can be calculated by taking into account both the force needed to support the player's weight and the additional force to accelerate. During the acceleration phase, the player's power output can be calculated by dividing the work done by the time taken to do it.