Science Final Exam Review

Both balls will hit the floor at the same time because the force of gravity acts on both objects equally, regardless of their initial velocities or methods of falling. The mass of the balls does not affect the rate at which they fall. Therefore, both balls will experience the same acceleration due to gravity and will reach the floor simultaneously.

A flat sheet of paper and a wad of paper with the same mass would not fall through the air at the same time due to air resistance. Air resistance is the force that opposes the motion of an object through the air. The wad of paper, being more compact and less spread out, would experience more air resistance compared to the flat sheet of paper. This increased air resistance would slow down the wad of paper more, causing it to fall at a slower rate than the flat sheet of paper.

Sliding friction is the correct answer because it is the type of friction that opposes the motion of two surfaces sliding past each other. When two surfaces slide against each other, the irregularities in their surfaces create resistance, resulting in sliding friction. This type of friction is commonly observed when objects are pushed or pulled across a surface, such as when a book is dragged across a table.

Rolling friction is the correct answer because when a rolling object moves on a surface, the friction between the object and the surface causes it to gradually slow down and eventually stop. This type of friction occurs when there is contact between the rolling object and the surface, and it acts in the opposite direction to the motion of the object. Rolling friction is typically lower than sliding friction, which occurs when an object slides across a surface, and static friction, which prevents an object from moving when a force is applied to it.

Static friction is the type of friction that prevents two surfaces from moving past each other. It occurs when two objects are in contact with each other but not moving relative to each other. The force of static friction acts in the opposite direction of the force applied to try to move the objects. It is the frictional force that must be overcome in order to initiate motion between the two surfaces. Once the objects start moving, the frictional force changes to kinetic friction.

Sliding friction is the force that opposes the motion of an object as it slides across a surface. When you push a box across the floor, there is a force of sliding friction acting in the opposite direction, which causes the box to stop when you stop pushing. Sliding friction occurs due to the microscopic roughness of the surfaces in contact, which creates interlocking between them and resists the motion. As a result, the box experiences a frictional force that counteracts its motion and brings it to a stop when the pushing force is no longer applied.

When two surfaces are not moving past each other, they experience static friction. Static friction is the force that prevents the surfaces from sliding against each other. It acts in the opposite direction of the impending motion and can vary in magnitude depending on the materials and the force applied. The value of static friction is always equal to or less than the force applied, keeping the surfaces in equilibrium and preventing any relative motion between them.

Weight is the force exerted on an object due to gravity, and it is measured in units called Newtons. Mass, on the other hand, is a measure of the amount of matter in an object and is measured in units called grams and kilograms. Therefore, the correct answer is Newtons.

The amount of gravitational force between two objects depends on their masses and the distance between them. This is because gravity is a force that weakens with distance. The greater the distance between two objects, the weaker the gravitational force between them. Similarly, the closer the objects are to each other, the stronger the gravitational force. Therefore, distance plays a crucial role in determining the strength of the gravitational force between two objects.

Weight is the measure of the force of gravity acting on an object. It is a measure of how heavy an object is and is dependent on the mass of the object and the acceleration due to gravity. Weight is typically measured in units of force, such as pounds or newtons. The greater the mass of an object, the greater its weight will be. Similarly, the greater the acceleration due to gravity, the greater the weight of an object will be. Weight is different from mass, as mass is a measure of the amount of matter in an object, while weight is a measure of the force acting on that matter.

Gravity is the force that every object in the universe exerts on every other object. It is a fundamental force of nature that causes objects with mass to be attracted to one another. This force is responsible for keeping planets in orbit around the sun, objects falling to the ground, and the formation of galaxies. Gravity is described by Isaac Newton's law of universal gravitation and Albert Einstein's theory of general relativity. It is a force that is always present and acts over long distances, shaping the structure and behavior of the universe.

The principle of conservation of momentum states that the total momentum of a system remains constant if no external forces act on it. In the case of a bowling ball striking the pins, the momentum lost by the bowling ball (due to its mass and velocity) is equal to the momentum gained by the pins (which are initially at rest). This is because the momentum lost by the bowling ball is transferred to the pins, causing them to move. Therefore, the principle of conservation of momentum is applicable in this situation.

Momentum is a property of a moving object that is determined by both its mass and velocity. It is a vector quantity, meaning it has both magnitude and direction. The momentum of an object can be calculated by multiplying its mass by its velocity. The greater the mass or velocity of an object, the greater its momentum will be. Momentum is important in understanding the behavior of objects in motion, as it helps to determine how they will interact with other objects or forces.

Air resistance is the force exerted by air on a moving object. As an object moves through the air, the air molecules collide with the object, creating a resistance force that opposes the motion. This force depends on factors such as the speed and surface area of the object. Air resistance is particularly noticeable for objects moving at high speeds, such as cars or airplanes, and it can significantly affect their motion and performance.

Centripetal acceleration is the correct answer because it is the force that acts towards the center of the curve, allowing the car to maintain its curved path. This force is necessary to counteract the tendency of the car to continue traveling in a straight line due to inertia. Without centripetal acceleration, the car would not be able to navigate curves and would instead continue traveling in a straight line.

When an object moves in a circle, it experiences a centripetal force that acts towards the center of that circle. This force is necessary to keep the object moving in a curved path and prevents it from moving in a straight line. Without this force, the object would continue moving in a straight line tangent to the circle. The centripetal force can be provided by various factors such as tension in a string, gravitational force, or friction. It is essential for maintaining circular motion and ensuring that the object stays on its curved path.

A ball thrown across a football field is an example of a projectile because it follows a curved path known as a trajectory. The ball is launched with an initial velocity and then moves under the influence of gravity, causing it to follow a parabolic path. The motion of the ball is independent of any external forces once it is in the air, making it a projectile.

The largest velocity reached by a falling object is its terminal velocity. Terminal velocity is the maximum velocity that an object can reach while falling through a fluid, such as air or water. When an object first starts falling, it accelerates due to the force of gravity. However, as the object gains speed, the drag force from the fluid increases and eventually balances out the force of gravity. At this point, the object stops accelerating and reaches a constant velocity, known as terminal velocity.

The given correct answer is Newton's 3rd Law of Motion or Newton's Third Law of Motion. This law states that for every action, there is an equal and opposite reaction. It means that when an object exerts a force on another object, the second object exerts a force of equal magnitude but in the opposite direction on the first object. This law is fundamental in understanding the interactions between objects and is widely used in physics and engineering.

Displacement is the correct answer because it refers to the change in position of an object in a particular direction. It takes into account both the distance traveled and the direction of travel. Velocity is the rate at which an object changes its position, distance is the total length of the path traveled, and inertia is the tendency of an object to resist changes in its motion. However, only displacement accurately describes the concept of direction and distance.

Positive acceleration refers to an increase in velocity over time. When an object experiences positive acceleration, it means that its speed is increasing. Therefore, positive acceleration indeed speeds up an object. Thus, the statement "Positive acceleration speeds up" is true.

Negative acceleration refers to the decrease in velocity over time. When an object experiences negative acceleration, it means that its speed is decreasing, causing it to slow down. Therefore, the statement "Negative acceleration slows down" is true.

Inertia is the property of matter that describes its resistance to changes in motion. It is directly related to mass, as objects with greater mass have greater inertia. This means that it takes more force to accelerate or decelerate an object with a larger mass compared to an object with a smaller mass. Therefore, the correct answer is mass.

A car engine converts the stored chemical potential energy in fuel into the kinetic energy of a moving car. As the fuel combusts, it releases energy that is used to drive the pistons, which in turn powers the car's wheels. This kinetic energy allows the car to move and perform work.

The total energy of a system remains constant. This means that the total amount of energy within the system does not change over time. Energy can be transformed from one form to another, but the total amount remains constant. This principle is known as the conservation of energy and is a fundamental concept in physics. It implies that energy cannot be created or destroyed, only transferred or converted into different forms. Therefore, regardless of any transformations or exchanges that occur within the system, the total energy remains the same.

Rubbing two sticks together creates friction between the surfaces of the sticks. Friction is the force that opposes the motion of two objects in contact with each other. When the sticks are rubbed together, the friction between them causes the molecules on the surfaces of the sticks to vibrate and generate heat. This heat energy is a form of thermal energy, which is the energy associated with the motion of particles within a substance. Therefore, the conversion of kinetic energy (from the rubbing motion) into thermal energy occurs due to the presence of friction.

Nutritionists use the term "calorie" to measure the amount of energy we obtain from the foods we consume. A calorie is a unit of measurement that quantifies the energy content of food. By understanding the number of calories in a particular food item, nutritionists can assess its potential impact on our energy intake and overall health.

The law of conservation of energy states that energy cannot be created or destroyed. This means that the total amount of energy in a closed system remains constant. Energy can only be transferred or transformed from one form to another. This principle is based on the understanding that energy is a fundamental property of the universe and is always conserved, regardless of the transformations it undergoes.

The energy stored in foods and fuels is potential energy because it is stored in the chemical bonds of molecules. When these bonds are broken, energy is released, which can be used to do work. This energy is in the form of potential energy because it has the potential to be converted into other forms, such as kinetic energy or thermal energy.

Henri Becquerel is credited with discovering that uranium is a radioactive element. In 1896, while conducting experiments with uranium salts, Becquerel accidentally discovered that photographic plates stored near the uranium emitted their own radiation. This led him to conclude that uranium was spontaneously emitting radiation, a groundbreaking discovery that laid the foundation for the field of nuclear physics. Marie Curie, on the other hand, is known for her pioneering research on radioactivity and her discovery of the elements polonium and radium. John Stilmoich and John Curie are not associated with the discovery of uranium's radioactivity.

Marie and Pierre Curie discovered the elements radium and polonium. Polonium is a highly radioactive element that was named after Marie Curie's home country, Poland. It was the first element to be discovered by the Curies through their groundbreaking research on radioactivity.

Attracted to

Gamma rays are a form of radiation that travel as waves. They have high energy and are able to penetrate through various materials. Gamma rays are produced during nuclear reactions and radioactive decay. They are often used in medical imaging and radiation therapy. Unlike alpha particles and beta particles, gamma rays do not have mass or charge, making them highly penetrating and capable of causing damage to living tissues. Therefore, the correct answer is gamma ray.

NOT nuclear fission

Fusion

The half-life of a radioactive element refers to the time it takes for half of the radioactive atoms in a sample to decay. It is a constant rate that is unique to each radioactive element. This means that regardless of the initial amount of the element, after one half-life, half of it will have decayed, and after two half-lives, three-quarters will have decayed, and so on. Therefore, the correct answer is half-life.

I-131 is the correct answer because it is a radioisotope commonly used in the detection and treatment of thyroid cancer. It emits beta and gamma radiation, which can target and destroy cancer cells in the thyroid gland. The radioactive iodine is taken up by the thyroid tissue, allowing for the detection of any abnormal growth or cancerous cells. Additionally, I-131 can be used in higher doses to treat thyroid cancer by destroying the thyroid tissue and any remaining cancer cells.

Radiation therapy is a common treatment for cancer that uses high-energy radiation to target and destroy cancer cells. It works by damaging the DNA of cancer cells, preventing them from growing and dividing. This can help stop the growth and spread of cancer. Therefore, the statement that radiation can be used to stop certain types of cancer cells from growing is true.

more useful

Radioactive dating is the correct answer because carbon-14, a radioactive isotope, is used to determine the age of fossils. Carbon-14 decays over time, and by measuring the amount of carbon-14 remaining in a fossil, scientists can estimate its age. This method relies on the principle that carbon-14 is constantly being produced in the atmosphere and taken up by living organisms, so when an organism dies, the carbon-14 begins to decay. By comparing the ratio of carbon-14 to carbon-12 in a fossil, scientists can calculate its age.

A chain reaction refers to a process where the subatomic particles released from one fission reaction go on to initiate additional fission reactions. In other words, the reaction becomes self-sustaining as the particles produced in each reaction go on to trigger more reactions. This continuous cycle of reactions is known as a chain reaction. Therefore, the given statement is true.

it moves more quickly

Gold-189 (Au-189) is sometimes used as a source of external ionizing radiation in cancer treatment.

In nuclear fusion, atoms of hydrogen are used to produce helium atoms with larger masses. This process involves the fusion of hydrogen nuclei, combining them to form helium. This reaction releases a tremendous amount of energy and is the process that powers the sun and other stars.

Iodine is used to detect thyroid problems because it is an essential element for the production of thyroid hormones. The thyroid gland absorbs iodine from the bloodstream and uses it to make hormones that regulate metabolism. By using an isotope of iodine, medical professionals can track the uptake of iodine by the thyroid gland and determine if it is functioning properly. This can help diagnose conditions such as hyperthyroidism or hypothyroidism.

Tracers are useful in determining medical problems because they allow doctors to track the movement of substances within the body. Radioactive tracers are commonly used in medical imaging techniques such as positron emission tomography (PET) scans. These tracers emit radiation that can be detected by specialized equipment, providing valuable information about the functioning of organs, blood flow, and the presence of tumors or other abnormalities. The radioactive nature of these tracers allows for accurate and detailed imaging, making them an essential tool in diagnosing and monitoring various medical conditions.

Elements with an atomic number greater than 93 are synthetic. This means that they are artificially created through nuclear reactions rather than occurring naturally. These synthetic elements are typically unstable and have very short half-lives, making them difficult to study and observe.

Radioactivity refers to the process of nuclear decay, which involves the spontaneous emission of radiation from the nucleus of an unstable atom. This decay can result in the release of alpha particles, beta particles, or gamma rays. Nuclear dating is not a correct answer as it is not directly related to the process of radioactivity. Similarly, nuclear attraction is not a correct answer as it does not accurately describe the process of radioactivity. Therefore, the correct answer is nuclear decay.

The formula for gravitational potential is GPE= m x 9.8 m/s(squared) x h, where GPE stands for Gravitational Potential Energy, m is the mass of the object, and h is the height of the object. This formula calculates the amount of potential energy possessed by an object due to its position in a gravitational field. The gravitational potential energy is directly proportional to the mass of the object, the acceleration due to gravity (9.8 m/s^2), and the height of the object.

Weight is the force exerted by gravity on an object. It is a measure of the mass of an object multiplied by the acceleration due to gravity. Therefore, something is never weightless as long as it has mass and is subject to the force of gravity. Even in space or on the moon, where the force of gravity is weaker, objects still have weight.