Earth's Gravitational Pull

In addition to cannonizing his three laws of motion, Newton also created the Law of Universal Gravitation, which makes it possible to determine the force of gravity between two bodies, such as the Earth and the moon.

Buoyancy

 Buoyancy is the "tendency of a body to float or to rise when submerged in a fluid," (Merriam-Webster). This phenomenon is the result of the increasing pressure of fluids at increasing depths. According to Pascal's Principle, this pressure applies in all directions; therefore, the pressure on the bottom of glass balls pictured is larger than that applied by air on the top of the balls, causing a net upward force on them.

Converging Lines

In looking at this picture, the lines which mark the edges of the hallway appear to converge in the distance; however, this is clearly not the case in actuality. This phenomenon occurs as a result of the linear perspective, a cue of the eye which allows human beings to perceive depth. This cue is related to relative size (how close objects are to an object of known size) and texture gradient(closer objects automatically appear larger). All of these enhance the experience of seeing and allow us to better perceive the nature of our environment. Additionally, artists utilize this knowledge of linear convergence in adding perspective to their paintings and drawings.

Swinging Back and Forth

 From a young age, children are attracted to the magic of the swing - or should I say the physics of it. Although it is true that toddlers' forward motion is provided by their parents' pushing of the swing, older kids manage to increase the speed of their motion without any external force helping them. This is explained by the theory of the parametric oscillator. By raising his/her body at the lowest moment of motion and lowering themselves at the highest, the child manages to increase his/her momentum, thereby lengthening the arc traveled on each swing.

Lighter Than Air

Although the force of gravity applies to most everything on Earth, some objects, such as this balloon, are able to remain above the ground. This balloon can float because it is filled with helium, which is a gas lighter than those which comprise our atmosphere. This should not be taken to mean that the balloon is actually defying gravity. The balloon is still being pulled towards Earth, but because it is filled with a lighter gas than others in the atmosphere, a relatively stronger force is exerted on the heavier gases, allowing the balloon to float above them.

Playing with Fire

One of the most interesting characteristics of fire is that it flickers. However, this motion serves a greater purpose than simply being aesthetically pleasing. While the heated air above the flame rises, cooler air moves toward the heart of the fire, containing more oxygen to fuel the growing flame. It is this occurrence which allows forest fires to create winds of hurricane proportions.

Tension

 Tension is a type of contact force which exists in a string, rope, wire, or cable when it is being pulled, specifically on both of its ends. In opposition to being pulled, the string applies an equal tension force on the objects, pulling them towards itself.

Tension is a vector, and therefore has a direction and a magnitude.

The force itself is called a tension force because the rope is in a state of tension.

Curves

As a result of the angle of a curve and the physics of centripetal force, which always works toward the center of a circle, a certain speed exists for which driving in a curve is ideal. Essentially, at this speed a person could drive smoothly without needing to press on the gas or the brakes, as long as he/she exerts an initial force while going into the turn.

Centripetal Acceleration

 Centripetal force is the force which allows an object to travel in a circular path. This force always acts toward the center of the circle in uniform circular motion; meanwhile, the velocity of the object remains linear (tangential to the path of the circle). The fact that the net applied force (and

the acceleration) is perpendicular to the direction of motion causes the linear velocity differ at every instant, creating a circular path for the object to follow.

Mousetrap Car

It is possible to create a car out of a common household mousetrap. How you ask? By attaching wheels to the moustrap, the turn of the back axel, which initiates the motion of the car, can be caused by the snap of trap.

Law of Acceleration

Remember that Newton's first law stated that an object with no net force acting on it will not accelerate. Newton's second law of motion, though, states that an unbalanced force (one that is not equally opposed by another force) acting on an object will cause the object to accelerate. The object's mass, which measures its inertia, also determines how much the object's movement will change. From this, Newton derived the formula a= F/m, where acceleration is directly proportional to force and inversely proportional to object mass. 

The Law of Inertia

Newton's first law states that an object has a certain inertia, which allows it to resist a change in its state. Mass is the measure of this inertia, and is measured in kilograms (if using SI units). As a result of this inertia, an object that is at rest will remain at rest, and one with a constant velocity will continue moving with that velocity, unless acted upon by another object.


Unless something moves this turtle, it will remain still until it chooses to move.

How Sharp is Too Sharp?

Although we may not think about it, the roads on which we drive are an application of physics. When they have to calculate the maximum degree until which a curve is safe for a car to make, engineers need to consider friction. Friction is defined as the resistance that one surface or object encounters when moving over another. It is what allows people to walk forward and cars to drive onward; without it, we would all remain in the same place, regardless of how much we tried to move. Engineers also use this concept when deciding on a safe maximum speed at which cars should drive (speed limit).

Energy Transfer

So I didn't have a picture of this one. Instead, I got it from http://eisforexplore.blogspot.com/2012/03/energy-transfer-for-kids.html, although I searched for it after planning my post.

When you drop a tennis ball placed on top of a basketball, the tennis ball bounces higher than it does when dropped alone, and the basketball does not bounce as high. When trying to understand this, take into account the energy transfer that takes place when the two balls come into contact. As the basketball begins to rebound, it hits the downward-falling tennis ball, thereby transfering some of its (the basketball's) energy to it (the tennis ball). For this reason, the basketball has less energy and therefore attains a lower height, while the tennis ball gains altitude.

Analyzing Projectile Motion

"Flying Cat"

To better understand projectile motion, we can analyze its vertical and horizontal components separately. The main motion equations we can use to do this are V=V0 + at, X=X0 + V0t + 1/2at^2, and V^2=V^20 + 2a(X-X0). Each of these equations can be used in respect to either X or Y values. For example, the first equation can be used to find the Y component (vertical component) of a projectile motion: Vy= Vy0 + ayt. *Also, in such a case, ay would actually be the acceleration due to gravity, or -9.81 m/s^2.

Projectile Motion

The water being shot up by these fountains is an example of projectile motion.

Projectile motion is defined as the parabolic path taken by an object after it has been thrown. Because such an object is not self-propelled and air resistance can usually be neglected, the acceleration of the object is that of gravity and is assumed to be constant. Since gravity is pulling the object down during its motion, which is defined as being up, gravity is defined as being negative (-9.81 m/s^2). Given the object's initial velocity and the angle at which it was thrown, several different aspects of its motion can be calculated.

Deftying Gravity

If gravity pulls all objects within range towards Earth, how do some objects, like planes, defy gravity? So, the specific example of an airplane actually requires a long explanation for its ability to fly. This explanation involves the concept of the airplane's wings generating a lift by making use of Newton's laws, along with several other concepts. What is important to understand, however, is that because a plane has its own acceleration and power, in addition to an aerodynamic shape and other aspects, it is able to push against the force of gravity (which is still acting upon it), take off into the air, and remain airborne for an extended period of time.



Aerial view of California

"What goes up, must come down."

Gravity causes my dog to land on the ground seconds after he jumps, rather than continuing to gain height.

Gravity. What is it, exactly? Well, gravity is the name of the force that pulls objects towards the Earth's core- it's the reason that objects stay within Earth's atmosphere. This force has different magnitudes for different large objects. Since gravity is related to object mass, the pull of gravity on Earth is stronger than the one felt on the moon, for example. On Earth, the numerical constant for gravity is 9.81 m/s^2, or about 32 ft/s^2.

Slice of Physics

Orange Tea Cake I baked- It was really good...

You probably haven't thought about this, but physics plays a large role in baking. Although there are several physics concepts involved in the process of baking a cake, we are only going to look at one specific example. Before you can even put the goey cake batter into the oven, you must preheat the oven. It takes some time for the oven to reach the necessary temperature (usually around 350 degrees Fahrenheit). During this period, the air within the oven begins to get hotter through the process of conduction, in which heat moves from an area of a high temperature to one of a lower temperature. Since hot and cold air have different densities, they cause each other to circulate. This is called convection. These processes repreat until the oven has reached the set temperature, after which time you can start baking your cake. :)

Welcome!!

Welcome to Everyday Physics! This is a blog dedicated to recognizing and understanding the role of the science of physics in everyday life. I am no physicist- just your average AP Physics student, trying to take a proactive role in the learning of abstract concepts. If you have any ideas or topics that you would like me to consider posting about, please feel free to let me know. Also, I will try to upload my own photos to correspond with the short blurbs I write.