TOP TEN FORMULAS AND EQUATIONS OF PHYSICS!

Top Ten Laws and Formulas of Physics

1.      Newton’s First Law

Newton’s first Law of Inertia states that an object in motion will stay in motion and an object at rest will stay at rest unless acted on by a net force. This concept is important because it is the basis for most physics concepts. An example of Newton’s first law would is used when you are in a car, and toss a coin up in the air. The coin will land in your hand and not behind you because the car, coin, and you are in motion and will continue to stay in motion until a net force acts upon you!

2.      Speed=distance/time

This concept is important to physics because it is the basis of many of the physics equations that we have learned throughout the year. Through this equation we are able to learn that Acceleration is equal to change in speed/time. With these equations, we were able to solve many physics problems. For example, if a car has gone 4 meters in 2 seconds, you can plug this information into the equation (speed=4/2) to find out that the car is going 2 meters a second.

3.      Distance traveled=1/2(acceleration x time²)

This equation, d=1/2 gt² was very important to learning about falling objects. Using the equations I had learned beforehand, I was now able to solve problems that asked me to find the distance that the falling ball had traveled. Know that I knew the basic physics equations, along with v=gt or velocity is equal to acceleration times time, I was able to solve most distance and time problems!

4.      Newton’s second law

      This law states that the acceleration of an object is directly proportional to the net force acting upon the object, and is in the direction of the net force which is inversely proportion to the mass of the object, or better known as Acceleration is proportional to net force/mass. This law was useful, because it was then that we began to learn about free fall. Using this equation I learned that in free fall, weight will be equal to resistance, so all objects no matter size of weight will fall at the same rate! While learning about this subject, we learned by example that a feather and a penny will fall at the same rate in free fall, because force of the object will be equal to the mass, so the acceleration will always be equal in free fall!

5.      Newton’s Third Law

Whenever one object exerts a force on another object the second object will exert an equal and opposite force on the first, or in a condensed version, every action has an equal and opposite reaction. This law is extremely important to physics because it is something that you don’t think about very often, but is needed for humans to live. Examples of newton’s third law would be if I was walking, I would push the floor backwards, and the floor would push me forwards, allowing me to walk, but the force would be equal and opposite. That is why, if I attempted to throw a piece of paper, it would not go very far because I can only exert a much force on the paper, as it can on me, and since it does not have very much mass, I cannot throw it very far!

6.      Work=fd Power=work/time

The formulas for work and power were very important to our class this year. While learning that work is equal to force times distance, we also learned that a Watt is how quickly work is done. This would later be beneficial to many of the equations that we would solve. By learning about power we could later apply this to how to power a light bulb through the equation I=V/R, but we would have not been able to find that out if it was not for the power and work equations. This concept showed me that in order to understand physics; you must understand all parts of the science.

7.      The change in Kinetic Energy is equal 1/2mv² and work

This formula is very important to our class because the change in KE is also equal to work. This equation allowed us to learn the answers for many questions such as how airbags keep us safe from getting hurt, to why there is padded grounding in gymnasiums. I learned that airbags keep us safe, because when you are in a car crash, you go from moving to not moving very quickly , and momentum is P=mv. The change in momentum is the same regardless of hitting the dashboard or the airbag. Because the change in momentum is constant, the J or impulse is constant also, so the airbag will increase the distance so that the force will be reduced in the equation J=f x the change in time, so the airbag will spread the force out over a longer period of time, making your chances of being hurt go down.

8.      Centripetal Force and Centrifugal Motion

While learning about these concepts, I learned that centripetal force is a center-directed force that causes an object to follow a curved path, while centrifugal force is the apparent outward force on a rotating body. I was able to connect these physics concepts by finding out the answer to why we move while in a turning car. I learned that centrifugal force doesn’t actually push you into the car door, but the real reason you hit the side of the car while turning is because NO force is acting upon you. Newton’s first law states that an object in motion will stay in motion unless a net force acts upon it, so in this case, since the car was moving in one direction and then changed, your body will continue to want to go in that direction but the car door will act as the net force that hits me and forced me to move towards the center of the circle that the car was making during its turn. Because of newton’s third law, I will push the door in, and the door will push me out, and so I will stay safely in the car.

9.      I=V/R

This formula states that current is equal to voltage divided by resistance. In order for current to flow there must be an electric potential difference. This is why it can be dangerous to plug an American appliance in into a European socket. European sockets have a much higher voltage, meaning there is a higher electric potential difference so there will be a lot of current running through the appliance. Our devices are not meant to have such a high amount of current running through them, so it may start a fire but because the European appliance expects a higher current, a lower current coming from an American appliance will not hurt the appliance or start an electrical fire.

10.   Opposite charges attract and like charges repel

We learned this concept while dealing with magnets. I learned that the charge of the

magnets always flows from south to north, and when opposite charges are near each other, they will be attracted, but if they are like charges, they will repel from each other. I learned that the reason your hair becomes frizzy after brushing it is because when you brush it, the brush will steal electrons from your hair, making your hair have a positive charge. Then the comb will become negative because of the stolen electron’s charge. We now know that like charges repel, and so your hair will stand up to get away from the other strands of hair.