# Isaac Newton’s Laws of Motion and Forces

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Most people are unaware that they are obedient to three laws that seem to govern the entire universe. A brilliant man named Isaac Newton proposed these laws during a life consumed by scientific experimentation. He was always curious about everything under the sun. He wanted to know what caused objects to move faster or slow down. He wanted to know what happens when a push or shove (formally known as a force) is thrust upon an object. As if answering the first two questions were not satisfying enough, Newton wanted to be able to explain what provides the pushing that causes an object to move. Many years into the future after Newton passed on, scientists came to credit him with finding logical answers to those and many other questions. They are answered by what is known as Newton’s basic laws of physics.

In a video where a science teacher presented the material, an otherwise boring subject suddenly became interesting. There was no better way to demonstrate and explain the Newton’s laws than using simple objects. For example, using an apple on a solid surface, the film showed that if a force (like an arm) pushes or hits the apple, it will accelerate as it moves away. Using heavy weights of two different sizes, the video showed that there is always more than one force acting on an object. It is the thing pushing the weight as well as the mass of the object working against it. Every action receives an opposite reaction.

It seems like physics is like sugar-coated math. The video showed the formula for figuring out a numerical value for the force exerted on an object. It is equal to the mass of the object multiplied by the acceleration. If a person knows any two of the variables in that equation, it is easy to calculate the value for the third variable. This video is important for grasping a basic understanding of gravity, force, mass, weight and other vocabulary terms.

Mr. Griff Jones is a very entertaining physics teacher. He applied physics to real life in a way that was both educational and startling. No one can watch this video and fail to understand the importance of wearing a seatbelt.

Sometimes a car crashes and the driver survives. Other car crashes have fatalities. The reason for each scenario has to do with physics. The main vocabulary for this program includes terms like: momentum, inertia, impulse, vector, mass, acceleration, velocity, mass, potential energy and kinetic energy. These terms are used in special mathematical formulas for determining things like force and momentum. For example, F= M x A is used to determine impulse and the formula P = MV is used to determine momentum. The momentum of a moving object can be changed by an impulse. In addition to using crash dummies to show how physics affects passengers, the teacher used an egg. If an egg is tossed against a soft surface that allows it to stop moving slowly, the shell will not break open. However, if the egg hits a solid surface that makes it stop moving abruptly, the shell will break.

That means that if a person is driving in a car, they can avoid an injury if they come to a slow stop instead of slamming hard on the breaks and jerking forward. Scientists test vehicles in a huge laboratory. They create front-end and side impact collisions. The experiments are always aimed at improving crash survival rates by designing safer cars. The video did not show rear-end collisions but most likely cars are tested every possible accident scenario. If a car’s main passenger compartment resists crumbling in an accident, then it gets a high score in the crash test (also known as crash-worthiness).

The biggest thing that stood out from the video was learning that when a car hits another car or a wall, the energy that was carried with the car (known as kinetic energy) does not go away. It is transferred and will affect the passengers. It validates Newton’s law called the Conservation of Momentum.

A biologist would be wise to understand physics. Equally so, Mr. Griff explained why a physicist should understand biology. These two branches of science are not independent of one another. In fact for a person who works as a biomechanic, their daily job is to apply these two branches of science to explaining how car crashes affect the human body. Three things were used explain how the body gets injured in car wrecks: the crash dummies, a transparent head with red solid material for a brain and a gel-filled cylinder.

Crash dummies help engineers understand why organ injuries result from crashes. They have internal sensors and material synonymous with bones. It allows engineers to quantify how much stress and strain is imposed on the body during a collision. Their ability to mimic a human body in a car crash is called biofidelity. Collisions occur between the internal body parts and the hard bones that protect them. For instance the aorta can rip away from the heart while the rest of the heart might remain intact. A person could have no bumps or bruises in an accident, but die from heart failure. Another part of the body that gets injured in the car is the brain. It might not hit the windshield during a collision (due to airbags) but the soft brain tissue could slam against the front and back of the skull. Mr. Griff demonstrated this using an award winning, transparent model created by another high school student. Lastly, in a gel-filled cylinder, some of contents spilled out when it was slammed into another surface. The part of the gel that was secured by the casing remained intact. These were fantastic illustrations that showed how the body can be hurt in a car crash.

The main vocabulary terms featured in this video were: stressors (such as tensile, sheering and comprehensive), pressure and forces. The teacher also discussed the body cavities, organs and bodily systems using an anatomical model. Stressors are produced from pressures and forces that act on the body. In conclusion, this video demonstrated how fragile and vulnerable the human body is. All of the safety measures in the world are worthless if people do not wear a seatbelt and drive carefully.