Question

Because movie producers have come under pressure for teaching children incorrect science, you have been appointed to help a committee of concerned parents review a script for a new Superman movie. In the scene under consideration, Superman rushes to save Lois Lane who has been pushed from a window 300 feet above a crowded street. Superman is 0.5 miles away when he hears Lois scream and rushes to save her. He swoops down in the nick of time, arriving when Lois is just 3.0 feet above the street, and stopping her just at ground level. Lois changes her expression from one of horror at her impending doom to a smile of gratitude as she gently floats to the ground in Superman's arms. The committee wants to know if there is really enough time to express this range of emotions, even if there is a possible academy award on the line. The chairman asks you to calculate the time it takes for Superman to stop Lois's fall. To do the calculation, you assume that Superman applies a constant force to Lois in breaking her fall and that she weighs 120 lbs. While thinking about this scene you also wonder if Lois could survive the force that Superman applies to her.

Answer 1

Initial height of Lois Lane is

Velocity of Lois Lane when she reaches above ground,

Now the Superman catches her, comes to a stop at ground. in time .

Acceleration of Lois Lane during this time is

So time taken by Lois Lane to change her expressions from horror to smile is , which is not possible in reality.

Net force acting on her is

Super man applies a force of in upward direction.

Lois Lane cannot withstand such a large force in reality.