How to Move a Boulder With a Small Force & a Pry Bar
Whether you are landscaping, teaching a high school physics lesson or training to be a tough gladiator fighter, you can move a boulder with minimum brute force, a little "know-how" and a pry bar. Using physics and algebra can help you determine the amount of force needed to roll the boulder. Does this Spark an idea?
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Instructions
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Understanding the Concept of Force
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1
Understand the concept of force in physics. You can easily calculate the amount of force applied necessary to move the boulder, which will enable you to develop a strategy for moving the boulder with less effort.
Use the equation for potential energy: Potential Energy (PE) = Work (w) = mass x height x gravitational force ( m x h x g = PE = w)
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2
Calculate the three factors of gravitational potential energy.
Measure the height of the boulder from the ground for the value (h). If the boulder is on the ground (height of zero), h = quotient of 1.
Measure mass (m). You can use a small rock that is similar to the boulder to find the density. Weigh the smaller rock. Multiply this weight by the scale ratio of the small rock to the boulder. For example, if the rock is one-tenth the size of the boulder, multiple the mass of the rock by 10 to find the mass of the boulder.
Assume a gravitational force of 32 feet per second squared, based on Newton's Law of Gravity.
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3
Use the equation for potential energy: Potential Energy (PE) = mass (m) x height (h) x gravitational force (g).
Multiply the three factors you found in Step 2. This is the potential energy, or how much energy you will need to be able to move the boulder.
For example:
If the mass of the little rock is 1 pound, the potential energy of the boulder will be 32 (g) x 10 X 1 pound (m) x 1 (h) = 320 pounds (PE). -
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Calculate the force (f) you will need to apply.
Remember that potential energy (PE) is equal to work (w), the amount of energy needed to move an object from rest. Now that you know the potential energy of the boulder, calculate the force you will need to apply to the pry bar.
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5
Choose the length of a pry bar. Because the nature of the equation (PE = m x g x h) is inversive, the longer pry bar you use means the amount of force you will need to apply minimizes. Therefore, choose the longest pry bar available.
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6
Divide the potential energy (PE) found in Step 3 by the height of the pry bar (h). The result is the force you will need to apply.
For example:
PE = work = 320 pounds = 10 feet (h) x force. Therefore the force you need to apply is 32 pounds, or 320 divided by 10.
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7
Use the spring scale to pull the pry bar down. Hook the scale to the pry bar to illustrate how much force is being used. This will impress your students, neighbors and family as they marvel at your strength, intelligence and physics knowledge.
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