by: Doug L.

What do you think happens to an egg when it hits the ground after being dropped from great heights?  It smashes if it is pavement, or coarse ground that it is falling onto, but what if it were softer? If the egg were to land on soft cotton or a mound of down feathers, the time of impact between the egg and these soft surfaces would increase greatly, therefore increasing the impulse. Due to this increase in impulse, the egg is less likely to break when its momentum is slowed to a halt rather than stopped abruptly. This is a great example of how momentum changes.

Description of Egg Case:

The egg case I have developed is quite simple. I found an old cardboard shoebox and I softened it by beating it with a baseball bat. I did this several times, even adding tape to it so that it wouldn’t fall apart as I whacked it. My reason in doing this was to make it so that the outside would give when it hit the ground. After softening the box, I filled it with crumpled newspaper and shredded printer paper. The reason in filling it with such soft material is so that the time of impact is increased greatly as it hits the ground. Therefore, the impact force can be decreased enough so that the egg inside might not break.

What is momentum?

Why did the egg cases have approximately the same change in momentum when they hit the ground?

-Momentum is the product of the mass and velocity of an object.

-Since there was no air resistance on any of the cases, and gravity pulls with a constant force, the egg cases fell at the same velocity. Therefore, the egg cases all experienced the same change in momentum.

What is impulse?

Why did all of the egg cases have approximately the same impulse?

-Impulse is the product of force and time interval during which a force acts. J causes the change in p.

-Since impulse equals the change in momentum, and momentum is mass times its velocity, the mass was made a constant for this experiment. All of the egg cases had approximately weighed between .2kg and .5kg, therefore keeping the impulse almost the same for each box.

Did my egg break?

NO! The egg case that i constructed was able to increse the time of impact on the egg, therefore decresing the force of impact, and keeping my egg from breaking.

I can apply what I have learned about change of momentum in this activity to real world situations such as: Airbags in cars, which increase the time of impact of a head and upper body as it is thrust forward towards the dashboard during an accident; landing platforms for stuntmen, which protect increases the time of impact when a stunt man lands after jumping from a window; shock absorbers on cars and motorcycles, which decrease the impact force of a car running over a low dip or sharp bump; and springs under kick-boxing rings, which increase the time of impact when a wrestler hits the floor after being dropped.

Real World Situations:

In this picture, the shock absorbers on the truck's wheel increase the time of impact when it rolls over cars, therefore, the force of impact is decreased.

In this photo, there are springs underneath the wrestling ring so that the time of impact is increased as John Cena is slammed against the floor. Due to this, the force of impact is decrased greatly enough to not injure John as much.