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Question 1 – Essay
Motion is an important component in the study of physical sciences. Moving particles are molecules, atoms, or ions that exhibit kinematics (Jones, 2000). Kinematics is the study of how particles move in terms of displacement, velocity and acceleration. Displacement is a vector quantity describing the change of position of a particle (Richmond, 2008). Velocity, another vector value, describes this displacement over a period of time, showing both the magnitude and the direction of the movement (Richmond, 2008). The final vector value, acceleration, describes how the velocity changes over time (Richmond, 2008). We can measure these vector quantities simply by recording the magnitude of the displacements, and the time it takes to reach different points along the lines of the displacement. To measure displacement, we look at the distance between the initial and final points of movement, and to measure velocity, we divide this displacement by the time it took to reach the final position. Finally, to determine the acceleration we look at the change in velocity, and divide it by the change in time, where the changes in velocity can be determined by the initial and final values of these vectors (Richmond, 2008). These quantities can be empirically measured by devices such as stop watches and accelerometers, to determine instantaneous values. Through thoroughly understanding the concepts of motion, we can better understand how the world around us moves and operates, which is essential to the study of physics.
Within the macroscopic universe, everything around us is moving in some way. In the case of precipitation, objects falling from the sky exhibit two distinct forces: gravitational and air resistance. These forces can be discovered and related with the use of Newton’s Second Law, F = ma (Richmond, 2008). Precipitation, such as rain drops are interesting in terms of movement, because while they fall with gravity, they do not exhibit a net acceleration (The Weather Guys, 2013). This is because as the rain drops fall, they reach a point where the air resistance is equal to the objects weight, or force of gravity. When this occurs, there is no longer a net force on the rain drop, which by Newton’s Second Law, means that there is no longer a net acceleration. This point of velocity is termed the “terminal velocity”, and can be applied to any object falling from a distance (The Weather Guys, 2013). Through the study of the movement of rain, we are better able to understand how objects fall and move, vital to understanding kinematics. [“Write my essay for me?” Get help here.]
Within the microscopic universe, we find that particles abide by the same concepts of kinematics: displacement, velocity, and acceleration. For example, in the world around us, atoms are constantly colliding and scattering as they run into each other. For instance, if we hit a table with a stick, the electron clouds around the atoms will come together and transmit force, or mass and acceleration, between the two objects. The atoms themselves will be protected by the shells of electrons around them, which will deform, with a displacement, to move the nucleus away from the point of impact (Baragiola, 2003). This displacement of the atoms will occur at a distinct velocity and acceleration, abiding by the law of conservation of energy (Baragiola, 2003). Further, when we look at the electron clouds themselves, we see that they are held in stable orbits around the nucleus, due to the electromagnetic forces exerted upon them by the atoms (Baragiola, 2003). The negative charges of the electrons, and the positive charges of the nucleus cause them to be attracted to each other (Baragiola, 2003). When a chemical reaction occurs and electrons are pulled from one atom to another, due to stronger electromagnetic forces, the electrons themselves undergo a displacement, velocity, and acceleration in their movement, much like movement we observe macroscopically.
Both macroscopic and microscopic movement are governed by the same principles of kinematics: displacement, velocity, and acceleration. These vector quantities can help us to better understand all elements of physics, not just simple kinematic problems. Because of this, the study of motion is essential to better understand the principles of physical sciences.
Question 2
Newton’s Second Law of Motion is the principle that force is equivalent to mass multiplied by the acceleration (Second Law of Motion, n.d.). According to this, force is produced when a mass is acted on by an acceleration. The greater the applied mass, the greater the force. Similarly, the greater the applied acceleration, the greater the force. Newton’s Second Law describes how objects can be moved in the world around us. Because of Newton’s Second Law, we can inherently understand why heavier objects are more difficult to move, and why it’s easier for us to pick up and carry objects with less mass. [Need an essay writing service? Find help here.]
Question 3
Acceleration is rate of the change of velocity over a period of time. It is a vector quantity that exhibits both a magnitude and direction, and it can be both positive and negative depending on the direction of application along a particles line of displacement (Richmond, 2008). It can be related to velocity by dividing the change in velocity over a set period, by the time over which that period occurred. We can determine the acceleration of a particle or object at instantaneous points in time by looking at smaller intervals of time and velocity, along the line of displacement.
Question 4
Centripetal acceleration is the rate of change of tangential velocity. If an object is moving in a circle with a constant angular velocity, the tangential speed will be constant, but the direction of the tangential velocity will change as the object moves, such that the object continues moving in its same path (University of Winnipeg, 1997). The direction of the centripetal acceleration is pointing inwards towards the center of the movement, and the magnitude is related to the square of the angular velocity, times the tangential speed (University of Winnipeg, 1997).
Question 5
To make an atom neutral, it must have equal number of protons and electrons. Protons have positive charges, and electrons have negative ones, so an equal amount will allow these values to cancel. Neutrons themselves are neutral and have no charge, so they will not effect the overall charge of an atom. To make an atom have a charge of +1, it has to have one more proton than electron, giving it a positive charge of 1.
Question 6
The ‘Plum Pudding’ model of an atom stated that atoms were made up of positively charged matter that had electrons embedded within it (Encyclopedia Britannica, 2012). The Bohr Model stated that atoms had electrons orbiting around them in clouds or shells with different energy levels.
Question 7
Since high and low notes have different frequencies of sound, it makes sense that speakers can be specially designed to handle different ranges. Woofers are designed for lower-frequency sounds “low notes”, and are larger and move more slowly when they create sound. In contrast, tweeters are designed for higher-frequency sounds, or “high notes”. These types of speakers are very small, in order to produce the higher frequency sounds by vibrating more quickly (Ram Electronics, n.d.).
Question 8
Ultrasound is an imaging technique which transmits high-frequency sounds pulses through the body. When the pulses hit a solid surface, they are reflected and are picked up by the probe. The machine then calculates the distance from the probe to the solid surfaces, and the time it took to reflect to create a display of the distances and intensities of the sound echoes on a screen, to create a two-dimensional image (How Stuff Works, 2016). This is different from just sound, because it looks at the echoes that sound pulses make as they hit objects within the body.
Question 9
To isolate the experiment from higher frequency vibrations, it would be best to (B) put the experiment in a sealed chamber and evacuate the air (because sound cannot travel in a vacuum).
Question 10
Young’s Double Slit Experiment demonstrated that light and matter can exhibit characteristics of both waves and particles. Within this experiment, it was shown that waves that are split will later combine back together. When they are combined, they will exhibit a phase shift due to their different path lengths, which creates an interference pattern. The experimental setup was a light source illuminating a plate with two parallel slits, with a screen behind the plate displaying the light, and the interference it produced (S, 2016)
Question 11
A pinhole camera is a camera that uses a pinhole rather than a lens. Light passes through the pinhole and projects an inverted image on the other side of the box. The image is inverted because the light travelling from the top of the actual object will travel through the pinhole to the bottom of the image. Similarly, light from the bottom of the object will travel through the pinhole to the top of the image. This creates an inversion of the image.
Question 12
For total internal reflection of light, the light from a medium of one index of refraction must be incident on a medium of a lesser index. Therefore, the answer is (C).
Question 13Electroplating is when we plate one metal onto another via hydrolysis, either for decoration or to prevent corrosion. The process uses an electrolytic cell, which negatively charges a metal and dips it into a solution that contains positively charged electrolytes. The positive and negative charges attract and bring the metals together. The electrons will be transferred from the anode to the cathode, which will be coated with the anode metal (Libretexts, 2015).
Question 14
The type of current flowing from a wall socket is alternating current, or AC current. We use AC current for distributing power over distance because it’s easier to change voltages using a transformer. When we turn on an appliance that uses electricity in our homes, we are allowing 120 volts from the wall socket to force electrons through the appliance like water through a pipe (Hyper Physics, 2016).
Question 15
A regular incandescent light bulb stops working when it “burns out” because the tungsten filament wears too thin and breaks, breaking the circuit, so the answer is (D).
Question 16
A compass is a magnet that is free to rotate about a vertical axis that will line up in a North-South direction, along with the magnetic field. Electricity will make movement if the coils of wire carrying current are placed near a magnet. When the magnet’s poles and the coils of wire face each other, they will repel and cause it to move like an electric motor (Engineers Week, 2015).
Question 17
Magnets are attracted to ferromagnetic metals, such as iron. Most car bodies are made of aluminum, which is not a ferromagnetic metal, so the magnet will not stick to it. We can tap the magnet on different parts of the car to determine which are not magnetic (like aluminum), and which are ferromagnetic (like iron).[Click Essay Writer to order your essay]
Question 18
- is the INCORRECT way to determine the poles of the magnet.
References
Baragiola, R. A. (2003). Introduction and Collision Kinematics.
Encyclopedia Britannica. (2012). Thomson atomic model.
Engineers Week. (2015). MAKING MAGNETS WORK.
How Stuff Works. (2016). How Ultrasound Works.
Hyper Physics. (2016). Household Use of Electric Energy.
Jones, R. (2000, November 13). Particle Theory.
Libretexts. (2015, September). Electroplating.
Ram Electronics. (n.d.). WOOFERS, TWEETERS AND CROSSOVERS – HIGH, MID AND LOW FREQUENCY SPEAKERS AND CROSSOVER NETWORKS.
Richmond, M. (2008). Displacement, velocity, acceleration.
S, J. (2016). Young’s Two Slit Experiment.
Second Law of Motion. (n.d.).
The Weather Guys. (2013, September 10). How fast do raindrops fall?
University of Winnipeg. (1997, October 9). Centripetal Acceleration.
