As a 5.0 × 102-newton basketball player jumps from the floor up toward the basket, the magnitude of the force of her feet on the floor is 1.0 × 103 newtons. as she jumps, the magnitude of the force of the floor on her feet is

As per the third law of Newton (action - reaction), the magnitude of the force excerted by the floor on the feet of the basketball player is equal to the magnitud of the force that her feet exerted on the floor. So, the answer is that the magnitude of the force of the floor on her feet is 1.0 * 10^3 newtons.