# Does Height or Distance Affect Impact?

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#### Updated on Sep 07, 2012

Grade Level: 9th -11th; Type: Physical Science

### Objective:

To find out if falling objects dropped from a higher distance will hit a greater impact force than the same object dropped from a lower distance.

### Research Questions:

• Why will throwing the ball down rather than dropping it alter the results of the experiment?
• How do we know gravity is always 9.8 m/s²? What exactly is this?

Galileo Galilei was an Italian physicist, mathematician, astronomer and philosopher who played a promiment role in the Scientific Revolution. He supposedly dropped things from the leaning tower of Pisa in order to prove that all objects fall at the same rate, whatever their mass. We'll perform a similar experiment, and try to measure how height affects the force of impact.

### Materials:

• Small, hard ball (like a golf ball)
• Large clear box to hold sand inside
• High building with windows on one side or a ladder (please be careful)
• Ruler and meterstick
• Scale
• Pen and paper for notes

### Experimental Procedure

1. On the scale, weigh how heavy your ball is (convert to kilograms) and note this.
2. Measure the distance from where you are going to drop the ball (in meters) and the surface of the sand. Start at a lower distance. Note this distance.
3. Simply drop the ball from above, straight into the sand. Do not apply any force, which means...do not throw it into the sand.
4. Carefully take the ball out of the sand and measure the depth of the hole it made, if any.
5. Now repeat steps 2-4, but at higher distances. Remember to just drop the ball rather than throw the ball down..as doing that will alter your results.

The Calculations

Now we are going to calculate to find out the impact force of the drop for all the heights. Remember that gravity is always 9.8 m/s² (meters per second squared). We are going to calculate impact velocity with this formula:

• v = √2gh (square root)
• g= gravity
• h= height of the drop (which you should have recorded)

This will give us the impact velocity just before impact.

To calculate kinetic energy (in joules) we will need to use the formula: KE= ½ mv²

• m= mass of object in kilograms
• v= velocity

To find average impact force (in Newtons) using the work-energy principle:

d= distance after collision (which you should have measured in the sand)

So which had a greater average impact force?

Chart

 Distance After Impact Distance= ____________ m ____________ m

Terms/Concepts: Falling bodies/objects; Kinetic energy; Potential energy; Impact; Newtons and joules; Work-energy principle

References:

Sofia PC is currently a college student with a deep interest in science who is aspiring to become a writer. She writes about all sorts of things across all subjects including, but not limited to; science, crafts, and fashion. She hopes to become a good writer so she can share her thoughts and experiences with the world and future generations.