Project 1 Essay
As an example of Physics in our daily life activities we can consider the interaction between our foot and the road when we walk. According to Newton`s third law for every action force there is an equal and opposite reaction force. (Harris, W., n.d.). Force is the pull or push needed to do a work. A force exists as a result of interaction, whenever there is an interaction between the two objects there is a force acting upon each object. When one object exerts a force on the second object, the second object also exerts an equal and opposite force on the first object. So, when we push on something, then it is also pushes us back. When we walk, we push backward on the road, and the road also pushes us forward. These two pushing forces are the result of friction force between our feet and the road. The friction force enables us to walk normally, walking would be impossible without this friction force between the surface of the road and our feet. In our daily activities, when we play football, baseball etc. we use Physics in these activities. In an interaction between the baseball bat and a baseball the bat strikes a baseball, the baseball and the bat exert equal forces on each other in opposite direction. But, compared to the mass of the bat, mass of the ball is very small, and the baseball- bat interaction accelerates the ball on getting struck.
In our daily activities we use lots of machines, because machines are the devices that require less force to accomplish an amount of work. Levers are such an important tool that allows us to do a work with less effort. A lever is a rigid object that is free to turn about fulcrum or the part of lever that supports the length of bar, and force is exerted upon the lever arm at a specific point to lift or move heavy objects (load). The closer the fulcrum to the load, the less force required to lift the load. The closer the fulcrum to the force, the greater the force required to lift the load. Levers are divided into three classes. A first class lever has fulcrum at the centre between the force and load. In a second class lever the load arm is in between the fulcrum and the force arm, and the fulcrum is usually closer to the load, which reduces to force required to accomplish the work. In class three levers the force arm lies between the fulcrum and load arm. Due to this arrangement large force is required for the displacement of load. (Tucker, K., n.d.). In our daily activities we use varieties of levers to accomplish different types of work with less effort. Scissors, pliers, water pump, car jack, are the example of class one levers. Bottle openers are the example of second class levers, and example of class three levers are tweezers, an arm lifting a weight, spade, and shovel.
When we drive a vehicle with hydraulic brake system, we apply small amount of pressure on the brake pedal to stop it. Since the actual brakes require much greater force to stop the car the braking system multiply the small pressure applied by the foot, and the system transmit the force to the tires using friction, and the tires transmit the frictional force to the road to stop the car. When we press the brake pedal the pressure applied by the foot is transmitted through the enclosed fluid of the braking system. It is an application of Pascal`s law in our daily activities to achieve a greater force by an externally applied pressure. Pascal`s law states that when there is an increase in pressure in an confined fluid, the pressure is transmitted at every other point in the container. The hydraulic brakes use incompressible fluids to transmit the forces from one point to another, within the fluid. Most aircraft use hydraulic brake system, and Pascal`s law is applied in hydraulic car lift. (Hodanbosi, C., 2014)
The boiling point of water (or any other liquid) depends upon the pressure on its surface. Under the normal atmospheric pressure, boiling point of water is 100°C, and the boiling point varies with different atmospheric pressure. Applying more heat to an open pot of water, the liquid water convert into water vapour without the increase in temperature. If the pressure is reduced the boiling point of water will also be decreased, because the water molecules will escape the surface of water easily. If we increase the pressure on the liquid then it will be difficult for the water molecules to escape from the surface, and boiling point of the water will be increased. In a closed container the water and vapour are at same temperature with no space for the water molecules to escape. When heat is applied to the closed container it will increase the pressure inside the surface of the water with an increase in temperature of the system. The observation that water boils at higher temperature, when the external pressure is increased is applied in pressure cooker for faster cooking, with less consumption of fuel. A pressure cooker consists of a metal pot and lid. The lid had a rubber ring to seal off the space between the lid and the pot. A pressure regulator, safety valve of low melting point alloy, a vent to allow the steam to escape generated inside the pot is fitted on top of the pressure cooker. (Chen, L., Anderson, J., & Wang, D.,2009) In the cooking process the pressure cooker generates high pressure, which allows the water inside the pot to boil at a greater temperature higher than its normal boiling point. At the beginning of boiling, water absorbs heat, and converts into steam. The increased pressure inside the pressure cooker raises the boiling temperature of water. Once the temperature reaches the melting point of the safety valve, the valve melts, and releases the steam and pressure inside the cooker to prevent an explosion.
In our common experience, if we try to jump out of a speeding vehicle in the opposite direction of the vehicle or suddenly stop our movement we fall on the ground. So, we move forward in the direction of motion of the vehicle to avoid a fall. This activity is associated with Newton`s first law of motion. According to this law a body continues in its state of rest or uniform motion in a straight line unless it is compelled by some external force to change the state. (Bibel, G., 2013) When we try to jump out of the speeding vehicle we are also in motion and share the velocity of the vehicle, and the body continues in its state of motion unless it exercises some force to change the state. In other words, if somehow we could eliminate gravity and air resistance a ball thrown straight upward would continue to move upward forever.
During our regular physical activities of walking, playing, running swimming, etc., our body derive energy from the ingested food, and for powering car energy is derived from liquid fuel source. Energy is the ability to do work, and the tendency of energy is that it flows from higher concentration to lower concentration. Foods like carbohydrate, fat etc, and liquid fuels like gasoline have the highly concentrated potential energy stored in their chemical bonds. According to the law of thermodynamics, energy exists in different forms, and it can be converted from one form to another. The thermodynamic variable or entropy of an isolated system remain constant or increases with time, and entropy is the unavailable amount of energy to do work. In the process of our regular physical activities like walking, playing, running etc., or for powering car, energy is converted into different form, and high concentration of energy gets transformed into useful energy for the bodies and machines for normal function. Every time as the energy is converted, some of the energy becomes less useful. In our daily activities, food energy is converted into work and less useful heat energy, and the vehicle engines convert the fuel energy into work and less useful heat energy. In the process of energy conversion although some parts of the energy gets converted into low grade energy, but, there is no change in the actual amount of energy. In our daily activities, we use Physics according to the law of thermodynamics, and fuel our human body and the machines, and convert the energy into work. In our daily activities we use several electrical appliances like electric heater, bulb, washing, television, where the conversion of energy take place, and electrical energy is finally converted into low grade heat energy that heat up the atmosphere around us.
Bibel, G. (2013, August 2). The Physics of Disaster: An Exploration of Train Derailments [Excerpt]. Retrieved March 16, 2015, from http://www.scientificamerican.com/article/the-physics-of-disaster/.
Chen, L., Anderson, J., & Wang, D. (2009, June 19). Cooking Under Pressure: Applying the Ideal Gas Law in the Kitchen. Retrieved March 16, 2015, from http://www.cameron.edu/~garyb/CHEM1004Online/CaseStudy/pressure_cooking.pdf.
Harris, W. (n.d.). How Newton's Laws of Motion Work. Retrieved March 15, 2015, from http://science.howstuffworks.com/innovation/scientific-experiments/newton-law-of-motion4.htm.
Hodanbosi, C. (2014, June 12). Pascal's Principle and Hydraulics. Retrieved March 15, 2015, from http://www.grc.nasa.gov/WWW/k-12/WindTunnel/Activities/Pascals_principle.html.
Tucker, K. (n.d.). Levers Used in Everyday Life. Retrieved March 15, 2015, from http://www.ehow.com/info_8435160_levers-used-everyday-life.html.