Final answer:
In an elevator accelerating upwards, you would weigh more than usual because the scale exerts extra force. At a constant speed, you weigh the same, and in free fall, you would appear weightless.
Step-by-step explanation:
If you were to weigh yourself in an elevator that is accelerating upward, compared to your ordinary weight you would weigh more. When an elevator accelerates upwards, the scale must exert a force greater than your normal weight to accelerate you along with the elevator. This additional force results in a higher scale reading, making you feel heavier than you are at rest. In contrast, if the elevator moves upwards with a constant speed, there is no acceleration and the scale would read your normal weight.
When the elevator is in free fall, as in the case where the cable is cut, you and the scale would be in a state of free fall together, and no normal force would act upon you. At this point, the scale would read zero, rendering you weightless. This dramatic effect is a real-world example that Einstein himself used to illustrate the principles of acceleration and gravity's impact on weight.