In this scenario, we will analyze the change in momentum of a dropped egg as it hits the floor.  We will see what happens to the force and impulse on the egg if we change the stopping time.

Source: Egg Shot, Jasper Nance, Flickr

Scenario:  Compare dropping an egg directly onto the floor with dropping an identical egg the same distance onto a soft pillow.

When you drop the egg, it speeds up as it falls, and as it speeds up, it is gaining momentum from the impulse caused by the force of gravity.  When it hits the floor or the pillow, it stops due to an impulse in the opposite direction.  For both scenarios, assume that the egg attains the same speed before it is stopped, and therefore experiences the same stopping impulse.  Since the impulse is the same for both situations, if you change the stopping time, you change the force acting on the egg. 

• Egg Dropped On Floor:  Drop the egg from a given height (like a table top) onto a hard floor.  What happens?  (This is intended to be a thought experiment, but you can also try it at home with real eggs.  Just don’t leave a mess and make anybody mad at you.) 
• Egg Dropped On Pillow:  Get a large fluffy pillow and put it on the hard floor where the egg will fall on it.  Now drop an egg of the same size onto the pillow from the same height as the other egg.  Describe in your journal what happens to the egg.  Does it break? 

Analyze What Happens and Why?   The eggs are same mass. They fall from same height and have same velocity when they hit the floor and when they hit the pillow.  They have same final velocity after hitting the floor or pillow (zero).

In terms of what we have learned in this lesson, why did one egg break when the other didn’t?

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Check Your Answer

The hard floor stops the egg very fast. Time is small, so force is great. The egg hits the pillow; the time it takes to stop the egg is increased, so the Force that stops the egg is decreased.