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.